We look to state law to determine whether an individual is married or remarried. Social
                        Security Act § 216(h)(1)(A), 42 U.S.C. § 416(h)(1)(A); 20 C.F.R. § 404.345. The Act
                        specifies that the validity of a marriage between a surviving spouse and an insured
                        decedent is determined by the law of the state in which the decedent was domiciled
                        at the time of his death. In this case, that state is Kentucky. However, neither the
                        Act nor our regulations address which law governs the validity of the surviving spouse’s
                        remarriage to a third party. See Social Security Act § 216(h)(1)(A), 42 U.S.C. § 416(h)(1)(A); 20 C.F.R. § 404.345.
                        Although the regulations do not specify which state law we should apply, we believe
                        that the law of Kentucky should be applied because the marriage of P~ and G~ occurred
                        in that state. Even if we looked to the law of Ohio, where P~ now lives, under Ohio
                        law, the validity of a marriage is determined based on the state where it was solemnized.
                        See Mazzolini v. Mazzolini, 168 Ohio St. 357, 358, 155 N.E.2d 206, 208 (1958).
                     
                     Kentucky law favors marriage, and the presumption of a legally valid marriage is one
                        of the strongest known in law. See Pinkhasov v. Petocz, 331 S.W.3d 285, 293-94 (Ky. Ct. App. 2011). However, marriage is prohibited and
                        void “[w]here there is a husband or wife living, from whom the person marrying has
                        not been divorced.” Ky. Rev. Stat. Ann. § 402.020(1)(b) (West 2016). And, a court
                        may declare a marriage invalid if the marriage is prohibited. See Ky. Rev. Stat. Ann. § 403.120(1)(c) (West 2016). But, importantly, a declaration
                        of invalidity based on the marriage being prohibited may only be sought by one of
                        the parties to the marriage and no later than one year after the petitioner obtained
                        knowledge of the prohibited condition. See Ky. Rev. Stat. Ann. § 403.120(2)(b) (West 2016).
                     
                     P~ submitted a valid marriage certificate showing that she married G~ on October XX,
                        1987. Therefore, the strong presumption in favor of marriage would apply to their
                        marriage. The evidence also shows that P~ was still married to L~ at the time of her
                        marriage to G~. Although this marriage was prohibited under Kentucky law because P~
                        was already married, we believe that Kentucky would find that the marriage was merely
                        voidable, rather than void ab initio (from the start) because neither party acted within one year to obtain a court declaration
                        that the marriage was void.
                     
                     Kentucky previously treated bigamous marriages as void ab initio, but in 1980, the Kentucky Court of Appeals upheld a bigamous marriage from challenges
                        from the son of the deceased and his first wife. Ferguson v. Ferguson, 610 S.W.2d 925 (Ky. Ct. App. 1980) (citing Ky. Rev. Stat. § 403.120). The son challenged
                        the second wife’s ability to act as the administratrix of the deceased’s estate arguing
                        the second wife’s marriage was void ab initio because it occurred prior to the deceased’s divorce from his first wife. Id. at 926. The court held that although a bigamous marriage was described as “prohibited
                        and void” under Ky. Rev. Stat. § 402.020(1)(b), a third party could not collaterally
                        attack the marriage. Id. Instead, the court found that a declaration of invalidity of marriage could only
                        be obtained by one of the parties to the marriage, and only within one year after
                        obtaining knowledge of the prohibitive condition. Id. The court found that the son could not maintain a collateral attack on the marriage
                        because the enactment of Ky. Rev. Stat. § 403.120 “represented a conscious recognition
                        on the part of the legislature that a previous policy of allowing a collateral attack
                        on marriages created unfair, economic penalties for the surviving spouse.” Id. at 927 (citation omitted).
                     
                     In 1993, the Comptroller General issued an opinion that under Ferguson, a bigamous marriage was not void ab initio, but merely voidable. Matter of: Myrtle O. Morris, B-251520, 1993 WL 284903, at *2 (Comp. Gen. 1993). The Comptroller General found
                        that a Federal Survivor Benefit Plan annuity could be paid to the member’s second
                        wife, whom the member married more than two years before obtaining a divorce from
                        his first wife, because under Kentucky law the second marriage was not challenged
                        within one year and therefore was valid. Id. Because no action was taken to void the marriage, the Comptroller General found that
                        the marriage was valid and that the second wife qualified as an eligible widow entitled
                        to an annuity.
                     
                     Although P~ reportedly separated from G~ in 1988, there is no evidence that either
                        party took action to have a court declare their marriage invalid. Indeed, P~ reported
                        that she remains legally married to G~. Under the reasoning in Ferguson and the Comptroller General’s opinion, P~’s marriage to G~ was not void ab initio, but merely voidable and subject to challenge under Ky. Stat. Rev. §403.120 (West
                        2016). Because neither P~ nor G~ took any action to void the marriage, and because
                        there has been no divorce proceeding, it stands as valid, despite being “prohibited
                        and void.”