(dissenting). 1 respectfully dissent. Defendants, Raymond A. Kosinski and Comerica *808Bank, co-personal representatives of the estate of Charles L. Sumpter, deceased, appeal as of right from a judgment awarded in favor of plaintiff, Alana C. Sumpter, holding that an antenuptial agreement between plaintiff and Charles L. Sumpter, now deceased, was void.
On June 8, 1983, plaintiff signed, and on June 9, 1983, Charles L. Sumpter signed, an antenuptial agreement prepared by Raymond A. Kosinski, an attorney. Also on June 8, 1983, Alana C. Sumpter signed a statement consenting to being represented by Raymond A. Kosinski, although Kosinski had represented Charles L. Sumpter "for many years” and would represent Charles L. Sumpter as well as her in the matter of the antenuptial agreement. On June 9, 1983, the parties were married, she being around thirty years of age and he being around thirty-nine years of age. She was a college graduate, working as a trust officer for Manufacturer’s National Bank, and he was an operator and part owner of a substantial nursing home. On August 17, 1983, Charles L. Sumpter died. He died testate, leaving his property under an earlier will that did not include provision for Alana. Plaintiff claims Sumpter had promised to change his will to provide for her. In December, 1983, plaintiff started this suit to have the antenuptial agreement declared void. Richard John Sumpter, Charles Lynn Sumpter, and Kipling Thomas Sumpter, children of Charles L. Sumpter by his earlier marriage, sought to intervene, but their motion was denied by the trial judge. However, after plaintiff won her lawsuit in the trial court, as above indicated, and defendants appealed, the motion to intervene by Richard John Sumpter, Charles Lynn Sumpter and Kipling Thomas Sumpter was granted, although their motion for peremptory reversal was denied.
*809Also pending on appeal to this Court, but the subject of a separate opinion, is Docket No. 91256, entitled "In the Matter of the Estate of Charles L. Sumpter, deceased, Richard T. Sumpter, appellant, versus Alana C. Sumpter and Raymond A. Kosinski, co-personal representatives of the Estate of Charles L. Sumpter, appellees,” in which the probate judge entered an order removing Kosinski as personal representative of the estate.
After a six-day trial, the trial judge rendered an opinion from the bench, finding that the dual representation by Kosinski of both plaintiff and the decedent, Charles Sumpter, constituted constructive fraud and, thus, the antenuptial agreement was void. Indicating reliance on In re Benker Estate,1 he found a great disparity between the assets of Charles L. Sumpter, which were valued as high as $2 million, and those of Alana C. Sumpter, which were valued under $100,000. He said that requesting plaintiff to sign the antenuptial agreement on the day before her wedding when very substantial sums of money were involved was "a short period of time” within which to consult counsel of her own choosing. He said that when one party does not have independent counsel and there is dual representation, the attorney has the highest obligation and duty to deal fairly with both parties, to deal evenly with both, to represent each party to the best of his ability and to fully disclose everything of importance. Noting that Kosinski had much stronger ties to Charles L. Sumpter and his family and their business than to plaintiff, Alana C. Sumpter, the trial judge said that, nevertheless, Kosinski was the biggest proponent of and urged the antenuptial agreement on Charles L. Sumpter. He believed *810that Kosinski was "loyal” to Charles L. Sumpter and did not fully and vigorously represent Alana C. Sumpter. He mentioned that Kosinski refused to show Alana the executed last will and testament of Charles L. Sumpter, presumably then in effect. He called the antenuptial agreement harsh to Alana and emphasized her reluctance to sign. He believed Charles L. Sumpter was an experienced, sophisticated businessman, far more so than Alana. He then concluded the antenuptial agreement was unfair, inequitable and unreasonable.
In the antenuptial agreement, property of Charles L. Sumpter was listed with estimated values in the vicinity of $2 million. The property of Alana C. MacDonald (now Alana C. Sumpter) was also listed with estimated values of around $50,000. In consideration of their intended marriage, each party released all rights in the property of the other, except as provided in the ante-nuptial agreement. The agreement provided that if the parties were married and living together as husband and wife at the time of his death, she would receive the marital home in which they were then living, provided she was responsible for and paid off any mortgage or other claims that might exist against the home. The parties further agreed that, in the event of the death of either, the other party would accept "the terms and provisions” under the will in full settlement.
As indicated, defendants Raymond A. Kosinski and Comerica Bank, co-personal representatives of the estate of Charles L. Sumpter, appeal as of right. Permitted to intervene, Richard John Sumpter, Charles Lynn Sumpter and Kipling Thomas Sumpter, children of Charles L. Sumpter and intervening appellants, also appeal as of right. On appeal, appellants raise five issues.
First, appellants claim that the circuit court *811erred in holding that the antenuptial agreement was void. In his opinion, the trial judge placed reliance on Benker, supra, where the Supreme Court held that an antenuptial agreement must be based on fair disclosure of assets to be valid. In the within case, plaintiff did not plead a nondisclosure of assets. Consequently, the within case is not on "all fours” with Benker and is not controlled by Benker.
In Benker, the Supreme Court said that when certain factors are present, a rebuttable presumption of nondisclosure will be created. Those factors were: (1) the lack of any provision for the widow in the agreement; (2) the fact that the deceased husband had a very ample estate compared to the widow’s estate; (3) the modest life style of the decedent husband and the lack of any outward appearance of wealth; (4) the fact that there was no indication, in general or in specific terms, that either party was informed as to the property interest of the other; (5) the lack of independent counsel representing the widow; (6) the fact that the attorney who drafted the agreement could only testify as to his normal procedure, which included a discussion of assets, but did not include the disclosure of undisclosed assets; and (7) the fact that the scrivener testified that he was not concerned with what the widow would get. In dicta, the Benker Court also said:
In order for an antenuptial agreement to be valid, it must be fair, equitable, and reasonable in view of the surrounding facts and circumstances. It must be entered into voluntarily by both parties, with each understanding his or her rights and the extent of the waiver of such rights.[2]
In the within case, the Benker factors were *812applied in finding that the antenuptial agreement was invalid. The trial judge noted, however, that Benker was only being used as a guideline, because Benker dealt with the issue of nondisclosure of assets while, as indicated, the instant case did not allege nondisclosure. In fact, on the first day of trial he ruled on a motion in limine that evidence of nondisclosure of assets could not be introduced because it was not alleged by plaintiff. However, I do not believe it was error for the trial judge to consider the Benker factors as a guideline for determining whether the antenuptial agreement was "fair, equitable, and reasonable.” Not only were the factors pertinent according to dicta in Benker, but the same factors were pertinent to determining whether there was constructive fraud and whether there was sufficient consideration.
Defendants argue that Benker stands for the proposition that antenuptial agreements are valid so long as fair disclosure of assets was made. However, antenuptial agreements are contracts and have always been analyzed under general principles of contract law.3 Benker did not say that nondisclosure was the only ground for invalidating antenuptial agreements, but said that nondisclosure was an additional ground for invalidating antenuptial agreements because "[ajntenuptial agreements give rise to a special duty of disclosure not required in ordinary contract relationships so that the parties will be fully informed before entering into such agreements.”4 Therefore, I do not believe it was error to give consideration to general principles of contract law or to accepted grounds for constructive fraud in deciding whether the antenuptial agreement was valid._
*813A trial court’s factual finding will not be set aside unless clearly erroneous. Special deference is given to the trial court’s assessment of the credibility of witnesses.5 Unlike active fraud, and contrary to what defendants argue, constructive fraud does not require an intent to deceive. Constructive fraud has been defined as a breach of a legal or equitable duty that tends to deceive others, regardless of the moral guilt of the person committing the fraud.6
In the within case, the trial court considered the following factors: the disparity in net worth of plaintiff and Charles Sumpter; the time constraints under which plaintiff signed the antenuptial agreement; the understanding of plaintiff that she would be provided for by will; the prior representation of Charles Sumpter by Kosinski and their ongoing attorney/client relationship; the strong ties that Kosinski had to Charles Sumpter and his family by virtue of being named co-personal representative in Charles Sumpter’s will and co-conservator for the beneficiaries of the will; the loyalty of Kosinski to Charles Sumpter; the harshness of the terms of the antenuptial agreement; the reluctance of plaintiff to sign the antenuptial agreement and her mention of a will, both of which should have created caution in Kosinski; and the relative sophistication of the parties. Based on all these factors, the trial court found that there had been constructive fraud.
The trial judge placed great emphasis on the impropriety of Kosinski’s representing both plaintiff and Charles Sumpter, believing Kosinski’s actions were clearly a breach of his duty to plaintiff.
*814Defendants also argue that Kosinski’s failure to disclose to plaintiff the nature and extent of his relationship with Charles Sumpter should not have been considered because Kosinski was named a defendant in his capacity as personal representative and not individually. However, the basis of this suit was to have the antenuptial agreement declared void. While it was Kosinski’s conduct that led to a finding of constructive fraud, Kosinski was not individually being held liable for fraudulent conduct. Therefore, I do not believe it was improper to consider Kosinski’s breach of duty, even though he was not named individually as a defendant.
Defendants further argue that it was error to find for plaintiff on the "failure of condition” and "abandonment” counts of the complaint. Defendants’ argument is first based on MCL 700.140(1); MSA 27.5140(1), which provides that a contract to make a will must be in writing. However, this provision applies to cases where a contract to make a will is sought to be enforced. Plaintiff herein was not attempting to enforce a contract to make a will. Plaintiff was attempting to have an antenuptial agreement declared void. Evidence of an agreement by Charles Sumpter to make a will was being used collaterally to attack the validity of the antenuptial agreement. Therefore, the writing requirement of MCL 700.140(1); MSA 27.5140(1) does not apply.
Next, defendants argue that, assuming Charles Sumpter did say he would provide for plaintiff by will, his statement was merely an expression of intent, which does not create a contractual agreement. However, although expressions of intent may not be contractual by themselves, they may be considered with all other circumstances in de*815termining that a contract has been made.7 This would be a finding of the trial court that would not be disturbed unless clearly erroneous. Moreover, defendants confuse the distinction between enforcing a contract to make a will and using expressions of intent collaterally to invalidate the antenuptial agreement. There was no finding in this case that Charles Sumpter’s expression of intent constituted a contract to make a will. Nor was there any allegation that such a contract was made.
Defendants also argue that the trial judge erroneously found for plaintiff on the "mistake of fact or law” count of the complaint. However, the trial court ruling was based on constructive fraud, which merely requires that there was a breach of an equitable or legal duty that tends to deceive another.8 Therefore, since Kosinski breached his duty to plaintiff, her execution of the antenuptial agreement under the mistaken belief that she would be provided for by will was a proper additional ground for invalidating the antenuptial agreement.
Next, defendants argue that it was error to find for plaintiff on the "lack of consideration” count of the complaint. It is true, as defendants argue, that marriage is sufficient consideration to support an antenuptial agreement.9 However, sufficient consideration and adequate consideration are two different issues. Saying that marriage is sufficient consideration means that marriage, by itself, can operate as the consideration necessary for formation of a contract. However, the consideration may be sufficient to form a contract yet inadequate in the sense that one party gave up much more than *816the other party. Adequacy of consideration is generally not questioned by the court unless consideration is so grossly inadequate as to shock the conscience of the court.
In this case, plaintiffs "lack of consideration” count is actually an allegation of inadequate consideration. Plaintiff alleged that Charles Sumpter had over $2 million in assets and an annual income in excess of $250,000. However, under the antenuptial agreement, plaintiff would apparently receive property with a value of less than $50,000. While this disparity in net worth between Charles Sumpter and plaintiff bore on the adequacy of consideration matter, it also was a factor in finding constructive fraud. As such, consideration of this factor was not improper because it pertained to the issue of whether Kosinski was adequately representing plaintiffs interests.
Second, defendants claim that the circuit court did not have subject matter jurisdiction. Intervening appellants argue that the validity of the ante-nuptial agreement was not merely "ancillary” to the settlement of the estate, but that it was the crux of the settlement of the estate. They reason that, therefore, the probate court had exclusive jurisdiction. They go on to contend that, since the probate court had already assumed jurisdiction over the estate of Charles Sumpter, the circuit court should not have exercised its jurisdiction.
In this case, defendant Kosinski, but not the intervening appellants, made a motion to transfer the matter to the probate court, which motion was denied. Plaintiff argues that intervening appellants are precluded from raising the subject matter jurisdiction issue on appeal before this Court because they did not timely appeal from the trial judge’s order denying Kosinski’s motion. However, even if intervening appellants had made no motion *817in the trial court, they could still raise the subject matter jurisdiction issue on appeal because it may be considered at any stage of a proceeding. The actions of the parties cannot operate as a waiver of or consent to subject matter jurisdiction.10
The circuit court had subject matter jurisdiction over the instant case under MCL 600.605; MSA 27A.605, which provides:
Circuit courts have original jurisdiction to hear and determine all civil claims and remedies, except where exclusive jurisdiction is given in the constitution or by statute to some other court or where the circuit courts are denied jurisdiction by the constitution or statutes of this state.
Exclusive jurisdiction is granted to the probate court by MCL 700.21; MSA 27.5021 as follows:
The court has exclusive jurisdiction of all of the following:
(a) Matters relating to the settlement of the estate of a deceased person, whether testate or intestate, who was at the time of death domiciled in the county or was at the time of death domiciled without the state leaving an estate within the county to be administered.
(b) Trusts and trustees in the execution of wills and administration of estates of deceased persons.
(c) Proceedings concerning the internal affairs of trusts including proceedings concerning the administration and distribution of trusts and the declaration of rights or the determination of other matters involving trustees and beneficiaries of trusts, including proceedings to:
* * *
(d) Appointment of a guardian, limited guardian, *818or conservator in cases prescribed by law, resolution of any contested matter in respect to the estate or ward, and settlement of the estate.
If a matter is not one of exclusive jurisdiction, the probate court may exercise concurrent jurisdiction with other courts over matters that are ancillary to the settlement of an estate, such as those listed in subsections (a) through (k) of MCL 700.22; MSA 27.5022.
I do not find any Michigan cases deciding directly whether a claim contesting the validity of an antenuptial agreement is a "matter relating to the settlement of the estate of a deceased person” which would give the probate court exclusive jurisdiction. However, in York v Isabella Bank & Trust,11 this Court had to decide whether the probate court had exclusive jurisdiction over claims against a personal representative of an estate. The first two claims in York involved mishandling of estate assets. This Court said that the probate court had exclusive jurisdiction. The third cause of action in York was for intentional infliction of emotional distress arising out of the mishandling of the estate. This Court said that the probate court had neither exclusive nor concurrent jurisdiction.
In In re Kus Estate,12 this Court also held that a probate court has no jurisdiction over a breach of contract claim made by the personal representative of an estate. The breach of contract claim had nothing to do with administration of the estate, and a probate court does not become a court of general jurisdiction merely because an estate is involved. The probate court can only acquire juris*819diction when expressly granted it by statute. The personal representative in Kus brought the action against someone who purchased potatoes from the decedent and never paid for them.
The claim in the within case is based on contract, as was the claim in Kus. However, it is more closely related to the estate than the claim in Kus, because it affects the distribution of the estate. While it would seem that a claim affecting distribution of an estate might come under the exclusive jurisdiction of the probate court, that is not always so. MCL 700.22; MSA 27.5022 grants concurrent jurisdiction to circuit and probate courts over matters that would affect the distribution of an estate, such as construing a will or determining heirs. Therefore, since the probate court has not expressly been granted exclusive jurisdiction over claims attacking the validity of antenuptial agreements, and since the Legislature has granted concurrent jurisdiction over matters directly affecting the distribution of estates, I believe that the circuit court had jurisdiction over the instant case.
Plaintiff argues that this action is for reformation of the antenuptial agreement, which would be an equitable action over which the probate court has no jurisdiction.13 Plaintiffs complaint does not request reformation; rather, it requests that the antenuptial agreement be declared void. In his opinion, the trial judge did characterize the relief he was granting as being based on the equitable grounds of constructive fraud. Therefore, the necessity of equitable relief is another reason for finding that the probate court does not have exclusive jurisdiction.
Intervening appellants argue that, according to *820In re Cain Estate,14 once a court acquires jurisdiction, its jurisdiction cannot be interfered with by another court. Intervening appellants argue that the probate court acquired jurisdiction over this case by virtue of the probate of Charles L. Sumpter’s will. However, in Cain, an action was brought in probate court for removal of the personal representative. It was alleged that the personal representative failed to include a $25,000 bank account among the assets of the estate. The probate court decided that the bank account was not an estate asset, so that the personal representative had acted properly. An action was also filed in the circuit court, alleging that legal title to the bank account was with the estate. We held that the circuit court properly declined to exercise its jurisdiction because the probate court already had jurisdiction over the dispute.
Thus, Cain is clearly and easily distinguishable from the within case because, in Cain, the same issue was raised in both courts. In this case, the probate court’s jurisdiction over the estate of Charles L. Sumpter, deceased, does not necessarily give it jurisdiction over all matters involving the estate. As the Kus Court said, the mere fact that an estate is involved will not necessarily vest jurisdiction in the probate court. For these reasons, I decline to find error in the assumption of jurisdiction by the circuit court.
Third, defendants claim that the circuit court erred in denying intervening appellants’ motion to intervene. Intervening appellants have not made a timely appeal from the order denying intervention. MCR 7.204(A)(1) provides that appeals as of right must be taken within twenty-one days after entry of the order appealed from or after entry of an order denying a motion for new trial. The order *821denying intervention was signed on March 23, 1984. No appeal was taken until January 27, 1986, when a motion to intervene was filed with this Court. Therefore, review of the circuit court order of denial is precluded.
Even if the issue were reviewable on appeal, the order denying intervention was not erroneous. GCR 1963, 209.1, now MCR 2.209(A), which was in effect when the motion to intervene was made, provided:
.1 Intervention of Right. Anyone shall be permitted to intervene in an action
(1) when a statute of this state or a court rule confers an unconditional right to intervene; or
(2) by stipulation of all the parties; or
(3) upon timely application when the representation of the applicant’s interest by existing parties is or may be inadequate and the applicant may be bound by a judgment in the action; or
(4) when the applicant is so situated as to be adversely affected by a distribution or other disposition of property which is in the custody or subject to the control or disposition of the court or officer thereof.
Intervention is a matter of discretion with the trial judge.15
In the within case, the guardian ad litem of Kipling Thomas Sumpter filed a motion to intervene in the circuit court proceeding, alleging that the minor’s interests might not be adequately represented. After review, the trial judge found that there had been no showing that the minor’s interests might not be adequately represented.
I do not find any abuse of discretion in his ruling. A personal representative has the duty to *822protect the estate from unlawful demands.16 This includes "the obligation to protect the estate against every demand that is not legally enforceable and against all doubtful claims and obligations. He should interpose against such claims every legal objection that industry and care can furnish.”17 The minor’s interest as a beneficiary of the estate was to have the antenuptial agreement declared valid. There was no showing that defendants would not adequately represent the minor’s interest.
I also believe that the trial judge was correct in finding that the guardian ad litem of the minor had no standing to intervene in circuit court. Probate Court Rule 202.1(b)(1), which was effective when the motion was made, provided:
The court may, if it deems necessary, appoint a guardian ad litem to appear for and represent in the proceeding a minor, a protected person, or one who is or is alleged to be a legally incapacitated person or a developmentally disabled person.
The court rule was substantially the same in 1938 when our Supreme Court held that "the proceeding” applies to the probate court proceeding only. The probate court has no authority to appoint a guardian ad litem to represent a minor in a circuit court proceeding.18 The guardian ad litem herein was appointed by the probate court to act on behalf of Kipling Thomas Sumpter in the probate estate proceedings of Charles L. Sumpter. He was, thus, given no authority to represent Kipling Thomas Sumpter in the circuit court. For these *823reasons, I conclude that the trial judge was correct in denying the motion for intervention because the guardian ad litem had no standing to intervene.
Fourth, defendants claim that the circuit court erred by failing to sufficiently set forth findings of fact and conclusions of law. I disagree. The trial judge’s findings of fact were sufficient.19
Fifth, defendants claim that the circuit court erred in admitting evidence regarding alleged business dealings and financial records of Charles Sumpter. The trial judge admitted into evidence financial records of Charles Sumpter and of Fair-lane Convalescent Home. In response to a motion in limine, while he said that evidence of the value of the estate was not relevant because nondisclosure of assets was not an issue, he also said plaintiff did allege lack of consideration based on the disparity of values between Charles Sumpter’s assets and plaintiffs assets.
Defendants argue that since there was not any dispute that Charles Sumpter’s estate was worth over $2 million, then the subject records became irrelevant. I do not agree. Since there was an issue with respect to the relationship between Charles Sumpter’s assets and plaintiffs assets, the admissibility of these records became a matter within the sound discretion of the trial judge. While the question of admissibility may have been a close one, certainly there was not any error in admission of these records into evidence by the trial judge.
I believe that the other claims of error made by defendants are without merit and do not require reversal. Consequently, I would affirm the trial court’s judgment._
416 Mich 681; 331 NW2d 193 (1982).
Id. at 689.
In re Hepinstall’s Estate, 323 Mich 322, 327-328; 35 NW2d 276 (1948).
Benker, supra, p 689.
Kroll v Crest Plastics, Inc, 142 Mich App 284, 288; 369 NW2d 487 (1985).
Goodrich v Waller, 314 Mich 456, 461-462; 22 NW2d 862 (1946), quoting 26 CJ, Fraud, §§ 3, 4, pp 1060-1061; see also General Electric Credit Corp v Wolverine Ins, 420 Mich 176; 362 NW2d 595 (1984).
Groening v McCambridge, 282 Mich 135,140; 275 NW 795 (1937).
Goodrich, supra; General Electric Corp, supra.
Kennett v McKay, 336 Mich 28, 30; 57 NW2d 316 (1953).
Goodman v Bay Castings Div of Gulf & Western Industries, 49 Mich App 611, 625; 212 NW2d 799 (1973); see also Hastings v Hastings, 154 Mich App 96, 98-99; 397 NW2d 232 (1986).
146 Mich App 1; 379 NW2d 448 (1985).
136 Mich App 343; 356 NW2d 23 (1984).
Van Etten v Manufacturers National Bank of Detroit, 119 Mich App 277; 326 NW2d 479 (1982).
147 Mich App 615; 382 NW2d 829 (1985).
Dudkin v Civil Service Comm, 127 Mich App 397, 404; 339 NW2d 190 (1983).
In re Brack Estate, 121 Mich App 585, 590; 329 NW2d 432 (1982).
31 Am Jur 2d, Executors and Administrators, § 180, p 102.
King v Emmons, 283 Mich 116; 277 NW 851 (1938).
MCR 2.517(A); Birkenshaw v Detroit, 110 Mich App 500, 509; 313 NW2d 334 (1981).