We are called on again to address the subject of support alimony where the alimony recipient is cohabitating with a member of the opposite sex. The issue again addressed is the retroactivity of 12 O.S. 1981, § 1289, and its subsequent amendments.
The parties to this appeal were granted a decree of divorce by the District Court of Comanche County on January 10, 1979. It provided, in addition to property division and child support payments, that the appellant pay the appellee support alimony in the amount of $300 per month from December 1, 1978, through June 1,1993. Support alimony was subject to termination by the death or remarriage of the appellee.
On February 15, 1984, the appellant filed a motion to modify the support payments in Comanche County District Court. Appellant’s motion was grounded on the allegation that the appellee was cohabiting with a member of the opposite sex and that modification or termination of support was therefore justified under 12 O.S. § 1289(D).1
*1139Appellant’s motion was denied by the district court on March 12, 1984. The trial court ruled that to sustain the motion would give retrospective effect to the statute, which became effective October 1, 1979, over nine months after the divorce had been granted.
Section 1289(D) makes voluntary cohabitation of a former spouse with a member of the opposite sex grounds for the modification or termination of future support payments where the moving party proves a substantial change of circumstances of either party to the divorce relating to need for support or ability to support.2
Whether § 1289(D) should be retrospectively applied was addressed in Smith v. Smith, 652 P.2d 297 (Okl.1982). In the Smith case, the parties were granted a decree of divorce on February 15, 1979. After subsection D became effective, October 1, 1979, Mr. Smith filed a motion to modify his payments of support alimony on the ground that Mrs. Smith was cohabiting with a member of the opposite sex. The opinion held that 12 O.S.1981, § 1289(D) could have prospective application only because there was no language in the statute to indicate that the legislature intended to give retrospective effect to it.
After the Smith case was published in 1982, the legislature amended § 1289, adding subsection E:
Except as otherwise provided in subsection D of this section, the provisions of any divorce decree pertaining to the payment of support may be modified upon proof of changed circumstances relating to the need for support or ability to support which are substantial and continuing so as to make the terms of the decree unreasonable to either party. Only those installments accruing subsequent to the motion for modification may be modified.3
That subsection provides that any divorce decree may be modified. The movant need only prove changed circumstances relating to the need for support or ability to support which are substantial and continuing so as to make the terms of the decree unreasonable. Proof sufficient for relief under subsection D is similar, requiring “substantial change of circumstances of either party to the divorce relating to need for support or ability to support.” In spite of the language that “any” divorce decree may be modified, this Court held in Holdsworth v. Holdsworth, 720 P.2d 326 (Okl.1986), that the 1983 amendment did not apply retroactively to alimony provisions of a decree of divorce imposed prior to the effective date of the statute, November 1, 1983. Holdsworth concerned the reduction of support alimony due to a change in the movant’s financial situation.
Even before Holdsworth was published, the legislature in an apparent attempt to further clarify this statute, amended subsection E, stating that “The provisions of this subsection shall have retrospective and prospective application with regards to modifications for the purpose of obtaining *1140support....”4 In a further attempt to clarify the statute, the legislature has recently enacted yet another amendment to § 1289 in House Bill 1286.5 The new amendment in subsection G provides:
The provisions of subsections D and E of this section shall have retrospective and prospective application with regards to modifications of the provisions of a final judgment or order for alimony as support, or of a divorce decree pertaining to the payment of alimony as support, regardless of the date that the order, judgment, or decree was entered. The imperative language of the latest legislative amendment precludes an interpretation that would provide for prospective application only. The language of the amendments is progressively stronger and supports the conclusion that the legislature intended that trial courts have the power to modify support alimony payments regardless of the date that the divorce decree was entered.
Having made such a finding, we must decide whether the legislature has the power to retrospectively apply the statute. One method of examination is to determine whether the right to support alimony is vested. This approach has been the traditional method of determining whether a right is protected from invasion of the legislature under Article 2, §§ 7, 15 of the Constitution of Oklahoma. If the right is vested, the authorities are both clear and strong that it cannot be destroyed or impaired except by due process of law. Baker v. Tulsa Building & Loan Ass’n, 179 Okl. 432, 66 P.2d 45, 48 (Okl.1937). The Baker Court held that a right was vested when the right of enjoyment, present or prospective, has become the property of some particular person or persons as a present interest. Baker, 66 P.2d at 48.
An analysis of the statute under this approach would dictate that we determine whether support alimony is terminable or modifiable, and if so, we could conclude that the right is not vested because it would not be a present interest. This Court has held that death of either party will terminate alimony support payments absent agreement to the contrary. May v. May, 596 P.2d 536 (Okl.1979). Under § 1289, an award of support alimony is now terminable upon death, remarriage, or cohabitation with a member of the opposite sex. Like child support, under § 1289, it is now modifiable. Since support alimony is terminable and modifiable, then the right is not vested at the time of the decree, but only at the time each payment becomes due.6
The approach of determining that a right is not vested, and concluding therefore that no due process rights have been violated has been criticized.7 Describing a right as “vested” is merely conclusional, as the courts must decide what constitutes such a right.8 In Usery v. Turner Elkhorn Mining Co., 428 U.S. 1, 96 S.Ct. 2882, 49 L.Ed.2d 752 (1976) the Supreme Court of the United States examined the constitutionality of the Black Lung Benefits Act of 1972 because of its retrospective effect *1141upon coal mine operators, who attacked the Act on several grounds including that the Act violated the Fifth Amendment Due Process Clause. The Court upheld the constitutionality of the Act stating that legislation which readjusts rights and burdens is not unlawful solely because it upsets otherwise settled expectations. The test the Court used was whether the measure enacted by Congress approached the problem of cost spreading rationally. The majority opinion refused to decide whether a broader cost-spreading scheme would have been wiser or more practical under the circumstances, deferring to Congress on that matter.
The legislature generally may overcome the traditional bias against retrospective statutes as long as it rationally relates the legislation to a legitimate governmental purpose, and if that rational relationship is present, the law may be upheld even though it may impair recognizable property rights.9 As in Usery, the legislation before this Court is an attempt by the legislature to readjust the rights and burdens of the divorced parties in the area of support alimony. The regulation of marriage and divorce is entirely a legislative question, and one which should and must be controlled by legislative question, and one which should and must be controlled by legislative enactment. Irwin v. Irwin, 3 Okl. 186, 41 P. 369, 372 (1895). Accordingly, the property division and support have a legitimate governmental purpose. After support alimony has been set, the party receiving the support can only be said to have a settled expectation of continuing to receive that support, because the death of the supporting party would end the support. Had the parties remained married, a change in the financial circumstances of the parties would inevitably result in a change in their standard of living. Prior law did not allow for contingencies of changed circumstances as the amended law does. Such a provision is made concerning child support whenever circumstances render such a change proper. 12 O.S.Supp. 1986, § 1277. Likewise, the legislature has decided that changed circumstances in the area of alimony support should allow for changes in obligations and benefits provided between the parties. We find that the legislation before us is rationally related to the legitimate legislative purpose of regulating divorces.
Section 1289 of title 12, and its recent amendments provide that support alimony, no matter when awarded, is now modifiable. This leaves to the district courts the decision of whether or not to modify the support. All of the objections as to the equity of the situation, including consideration of the effect the award of support alimony had upon the property division, the reliance the parties had upon the law at the time of the divorce decree, whether or not the cohabitation of the former spouse with a member of the opposite sex continued after modification of the statute, and any other equitable matter may be considered by the trial court.
We herein hold that the intent of the legislature can be retrospectively effected. Accordingly, we overrule Smith v. Smith, 652 P.2d 297 (Okl.1982), and Holdsworth v. Holdsworth, 720 P.2d 326 (Okl.1986), reverse the order of the trial court, and remand this case for a disposition in a manner not inconsistent with this opinion.
REVERSED AND REMANDED.
DOOLIN, C.J., HARGRAVE, V.C.J., and HODGES, LAVENDER and WILSON, JJ., concur. SIMMS, OPALA, KAUGER and SUMMERS, JJ., dissent.. The 1983 amendment was in effect at the time the motion to modify was filed. See, 1983 Okla. Sess. Laws, ch. 86, § 1.
. Subsection D of 12 O.S., § 1289 was added, and became effective on October 1, 1979, 1979 Okla. Sess. Laws, ch. 278, § 1, and has been amended three times since then. See, 1983 Okla. Sess. Laws, ch. 86, § 1; 1985 Okla. Sess. Laws, ch. 188, § 1; and 1987 Okla. Sess. Laws, ch. 130, § 1, effective June 3, 1987. The statute provides:
The voluntary cohabitation of a former spouse with a member of the opposite sex shall be a ground to modify provisions of a final judgment or order for alimony as support. If voluntary cohabitation is alleged in a motion to modify the payment of support, the court shall have jurisdiction to reduce or terminate future support payments upon proof of substantial change of circumstances of either party to the divorce relating to need for support or ability to support. As used in this subsection, the term cohabitation means the dwelling together continuously and habitually of a man and a woman who are in a private conjugal relationship not solemnized as a marriage according to law, or not necessarily meeting all the standards of a common-law marriage. The petitioner shall make application for modification and shall follow notification procedures used in other divorce decree modification actions. The court that entered the divorce decree shall have jurisdiction over the modification application.
. 1983 Okla.Sess.Laws, ch. 86, § 1, effective Nov. 1, 1983.
. 1985 Okla.Sess.Laws, ch. 188, § 1, effective Nov. 1, 1985.
. 1987 Okla.Sess.Laws, ch. 130, § 1.
. The case cited by the dissent in footnote 6, Stanfield v. Stanfield, 67 Okl. 56, 168 P. 912, 914 (1917), supports the proposition that support alimony is terminable, and therefore is not vested. Stanfield holds:
Alimony decreed to a wife in a divorce is as much a debt, until the decree is recalled or modified, as any judgment for money is, and there is authority to the effect that the decree in favor of Mrs. Stanfield operated to cause an indebtedness to arise in her favor as each installment of alimony fell due. [Emphasis added, citation omitted.]
There is, in fact, support in our case law for the proposition that support alimony stands in a class by itself. The case of Grattan v. Tillman, 323 P.2d 982, 984 (Okla.1957) quotes Commons v. Bragg, 183 Okl. 122, 80 P.2d 287, 290 (1938) as follows:
[A]n order for the payment of alimony possesses different characteristics from an ordinary debt since it is designed to secure the performance of a legal duty in which the public has an interest.
. DeMars, Retrospectivity and Retroactivity of Civil Legislation Reconsidered, Ohio N.U.L.Rev. 253 (1983).
. 16A Am.Jur.2d Constitutional Law § 669 (1979).
. J. Nowak, R. Rotunda, & J. Young, Constitutional Law, 476 (2d ed. 1983).