(dissenting). The record shows in this case that in response to the plaintiff wife’s action for a money judgment on the parties’ May 22, 1973 separation agreement the defendant husband’s answer awkwardly alleged, *389inter alla, that through his mistake and her fraud the language of the written instrument failed to express their intention that his obligation to support their children would terminate on their emancipation.
Although the technical term “reformation” was not used during the course of litigation until this appeal, both parties deliberately and extensively elicited paroi evidence during the course of trial relevant to such relief.
It was not disputed that the parties alone, without benefit of counsel, sat down one day at their kitchen table and agreed that defendant would pay plaintiff $600 monthly to maintain the marital residence and support the children there. There was no conflict as to defendant’s moving out of the home, or as to such issues as custody, visitation or insurance coverage. The defendant denied negotiating the issue of a cost-of-living adjustment or contingencies affecting the monthly amount; plaintiff testified that defendant had refused the cost-of-living increase and payments for the children’s college education on the ground that the costs would “all even out as the years go by”. Having in mind the experience of their neighbor, whose husband had taken their children and moved into a new house, plaintiff said she and her husband specifically intended to provide enough support to maintain the marital residence for the benefit of their two children, who, at their age, needed the stability of their neighborhood friends and the familiarity of the home.
Plaintiff agreed with defendant’s testimony that they had never discussed under what circumstances, such as remarriage, the payments would cease. On redirect, however, she said she had “believe[dj” that he had been aware of the unconditional, perpetual nature of his obligation; she said this was an inference she drew from his refusal to agree to a cost-of-living adjustment despite the fact that he would have a good pension after 20 years’ service in the local police department while she was just starting out as a real estate sales agent.
After their kitchen table talk, an attorney representing plaintiff drew up the instrument executed May 22, 1973, which provides in paragraph ninth that “[t]he husband agrees to pay to the wife for the support and alimoney [sic] *390the sum of Six Hundred ($600.00) Dollars per month, recognizing that his income presently prevent [sic] him from paying more.” Defendant testified that he did not bother conferring with an attorney about the language of the instrument until plaintiff, during an argument subsequent to execution, warned him that he had bound himself to an unlimited obligation to pay her $600 monthly. After consultation with counsel, defendant understood that the language of the instrument was unconditional but he never intended to continue payments past the point at which both children were emancipated. He did not, however, stop or modify the payments even when plaintiff took in an adult male boarder in 1975 nor when the younger child moved in with him and subsequently entered military service. He stopped his payments to plaintiff and instead paid them into a bank account with himself as trustee for the benefit of the children as of July, 1978 because the older child was leaving home to attend college out of State and has since married. He nevertheless continued to deduct the full amount of such payments through the end of 1980 on his tax returns.
Trial Term found that the parties had agreed on the sum of $600 monthly as support for the children and upkeep of the marital residence, which at the time of trial in January, 1981 was owned by the parties as tenants by the entirety. It further found that at no point did either specifically address the issue of what portion, if any, of the installments was to be allocated to alimony when the children became emancipated or if the plaintiff remarried.
Since defendant had made payments under the agreement to his wife and on his own initiative to a bank account later while taking full advantage of the income tax deduction for alimony through 1980, the court awarded judgment to plaintiff for all amounts due under the language of the support provision up to the date of trial. Since the answer had sufficiently raised the issue of mistake, however, the court additionally ruled that it would strike from the separation agreement the entire support provision. The court reasoned that its language contemplated support of plaintiff and the children without allocation, and the court itself could not redraft it to reflect any *391particular allocation because the parties themselves had not addressed that issue in reaching their agreement in 1973. The court nevertheless left intact a provision giving plaintiff exclusive possession of the marital home, on the ground that no ambiguity appeared in the language making such provision.
It is clear on this record that Trial Term correctly struck the support provision in the exercise of its equitable power to reform the written instrument imperfectly expressing the parties’ limited agreement concerning alimony and child support.
It is well settled that the object of reformation is to conform the written instrument to the actual agreement of the parties (see Backer Mgt. Corp. v Acme Quilting Co., 46 NY2d 211, 219). Reformation is available only if the actual agreement is shown to be at variance with the terms as written through the mistake of a scrivener or of either party, no matter how it occurred (see Harris v Uhlendorf, 24 NY2d 463, 467; Nash v Kornblum, 12 NY2d 42; Hart v Blabey, 287 NY 257; Born v Schrenkeisen, 110 NY 55, 59; Meier v Brooks, 22 AD2d 56, 59). The mistake cured by reformation is not a mistake of fact or law under which the parties labored in entering the agreement. Instead, it is the error they (or their scrivener) made in failing to reduce the substance of their agreement to a writing drafted in such a way as to describe no more, and no less, than the limited issues as specifically resolved by their agreement (see Harris v Uhlendorf, supra, p 467; Nash v Kornblum, supra, p 47; Salomon v North Br. & Mercantile Ins. Co., 215 NY 214, 219; Christopher & Tenth St. R.R. Co. v Twenty-Third St. Ry. Co., 149 NY 51, 56, 58; Allison Bros. Co. v Allison, 144 NY 21, 30; Nevius v Dunlap, 33 NY 676, 680-681; Rider v Powell, 28 NY 310; Eastern Air Lines v Trans Caribbean Airways, 29 AD2d 379, 383, affd 23 NY2d 709; Stolitzky v Linscheid, 150 App Div 253).
A party relying on the instrument cannot defeat a claim for reformation on the ground of the other party’s failure to read or understand the instrument (see Hart v Blabey, supra, p 262; Albany City Sav. Inst. v Burdick, 87 NY 40; Meier v Brooks, supra, p 60; Raby v Greater N. Y. Dev. Co., 151 App Div 72, affd 210 NY 586; Jamaica Sav. Bank v *392Taylor, 72 App Div 567, 573-574). Nor is the failure to plea reformation a bar to such relief (see Susquehanna S. S. Co. v Andersen & Co., 239 NY 285; Born v Schrenkeisen, supra, p 60; Pitcher v Hennessey, 48 NY 415, 423; Hotel Credit Card Corp. v American Express Co., 13 AD2d 189, 194; Carvalho v Sudderly, 169 App Div 652, 655; Arlt v Whitlock, 65 App Div 246). Proof of the variance between the meeting of the minds and its expression in the writing must be clear (See Backer Mgt. Corp. v Acme Quilting Co., 46 NY2d 211, 219-220, supra). “‘“If the environment and the motive of the parties, the consideration and the necessities to be met, make the contract as it is written a highly improbable one, one for which there was no motive, or necessity, or consideration, then the writing has little self-supporting force, and a relatively small amount of clear and credible evidence will establish the mistake” ’ ” (Meier v Brooks, supra, p 60).
With the exception of plaintiff’s unpersuasive comment, contradicting her other testimony, that she “believed” that defendant had known his agreement was to be a perpetual and unconditional obligation, the testimony of the parties supports Trial Term’s findings to the effect that the parties never addressed and therefore never resolved the issue of how (and whether) defendant’s monthly payments were to be reduced or eliminated upon the children’s emancipation. The evidence shows their attention had been focused solely on the issue of keeping the marital roof over the heads of those children. It was, of course, inconsistent for Trial Term to reform the parties’ writing to eliminate the support provision at the same time it awarded plaintiff a money judgment under the same provision and preserved the provision granting plaintiff exclusive occupancy of the marital home. Since defendant failed to cross-appeal from the judgment, however, this court cannot cure the error. Furthermore, the parties’ failure to agree on the nature or extent of defendant’s statutory obligation of spousal support does not relieve defendant of that obligation.
Nevertheless, the record fully supports the trial court’s reformation of the instrument memorializing the parties’ separation agreement respecting alimony and child support — or, more accurately, maintenance of the marital *393residence and child support. As a matter of contract analysis under this equitable doctrine, the only question before the court was whether there had been a meeting of the parties’ minds upon the issue of the duration of the defendant’s separate alimony and child support obligations in light of the fact that, as found by the court after a hearing (see Wack v Wack, 74 NYS2d 435), the obviously significant issues of the children’s inevitable emancipation or the plaintiff’s remarriage had never arisen during the parties’ negotiations. That question, on this record, could only have been answered in the negative.
The statutory obligation of child support terminates upon emancipation (see Domestic Relations Law, § 32, subd 3; Family Ct Act, § 413; Social Services Law, § 101, subd 1). Thus the natural and logical inference to be drawn from the incorporation of this statutory obligation in a separation agreement is that the contractual obligation thus created is limited in duration to the children’s minority. An express provision terminating the undertaking upon emancipation would be superfluous.
It is of course true that the parties’ failure to allocate stated portions of defendant’s undertaking between child support and alimony would permit the drawing of an inference that emancipation was not intended to work a reduction in the amount of the undertaking because the entire undertaking would be subsumed under the head of alimony at that point. But it must be emphasized that these contradictory inferences remain inferences of fact.
There is simply no authority for the proposition that an unallocated, unitary provision for alimony and child support — in the absence of any term of limitation or condition — raises an irrebuttable legal presumption that the parties intended no modification of the undertaking upon the children’s emancipation. The parties’ failure to express the consequences of emancipation in their agreement certainly does not mandate a finding that their omission was intentional and that, accordingly, the undertaking was meant to be unaffected by emancipation.
Furthermore, since the court here had expressly found as a fact that during their negotiations, the parties had never even addressed the consequences flowing from emancipa*394tian, there is no basis for arguing that the court should nevertheless have ruled as a matter of law that the parties’ failure to allocate alimony separately from child support required it to declare that the entire undivided contractual obligation must continue in full force and effect so long as defendant was statutorily liable for either alimony or child support.
In the first place, the decisions, that have refused a reduction in an unallocated provision for alimony and child support upon emancipation merely construed separation agreements that, unlike the agreement proved here, contained express terms dealing with future contingencies such as emancipation or remarriage. Applying the standard rule for the construction of integrated written contracts, the courts merely concluded that the express inclusion of some contingency terms logically excluded their finding of any additional unexpressed terms. (See Nichols v Nichols, 306 NY 490; Rehill v Rehill, 306 NY 126; Stern v Stern, 41 AD2d 676, mot for lv to app dsmd 32 NY2d 704; Craig v Craig, 24 AD2d 588; Harwood v Harwood, 182 Misc 130, affd 268 App Div 974.) This analysis, however, would be relevant here only if defendant had challenged the meaning of the parties’ agreement rather than the fidelity of the poorly drafted written instrument to their actual agreement. This crucial distinction between interpretation and reformation was recognized by the Court of Appeals in both Nichols v Nichols (supra) and Rehill v Rehill (supra).
In the second place, the support provisions of a separation agreement are not an all-or-nothing proposition. The duration of the agreement to make periodic alimony payments need not be coextensive with the statutory obligation of support in order to escape invalidation by former section 5-311 of the General Obligations Law, which limited attempts to relieve spouses of their statutory support obligations (see Kromberg v Kromberg, 44 NY2d 718, 720; Seligman v Seligman, 78 Misc 2d 632, 634-635). Therefore, the trial court was not required to rule in the case at bar that as a matter of law, regardless of the parties’ agreement or lack thereof, defendant’s contractual undertaking to pay an unallocated periodic sum in satisfaction of his statutory alimony and child support obligations continued in full force and effect until both statutory obligations ceased by operation of law.
*395In sum, the evidence in the record adequately supported the trial court’s finding that the duration of the parties’ actual agreement on the subject of periodic alimony and child support payments was limited to the children’s minority. Because the parties had not considered their postemancipation obligations, they could not be said to have made any decision on either modifying or continuing the unitary payment provision. In other words, since they had not even adverted to the inevitable event of emancipation during their negotiations, their minds could hardly have met on a resolution of the consequences that ordinarily flow from that event. Nor is there any salutary purpose in discouraging such short-sighted agreements by indulging in a fiction that any such short-term agreement will be construed as governing the long term, regardless of the parties’ intentions or lack thereof.
Upon emancipation of the parties’ children, therefore, defendant’s contractual undertaking to pay periodic sums in satisfaction of his alimony and child support obligations terminated for lack of any agreement addressing his post-emancipation statutory liability. The trial court thus properly ruled that the entire provision for alimony and child support in the instrument sought to be reformed was no longer effective.
Accordingly, the judgment must be affirmed insofar as appealed from.
Titone, J. P., and Gulotta, J., concur with Gibbons, J.; O’Connor and Boyers, JJ., dissent and vote to affirm the judgment insofar as appealed from in an opinion by O’Con-nor, J.
Judgment of the Supreme Court, Westchester County, dated April 22,1981, reversed insofar as appealed from, on the law and the facts, with costs, and the third decretal paragraph is deleted insofar as it purports to annul the ninth paragraph of the parties’ separation agreement.