Many same-sex couples have been in committed relationships for years, even decades. Yet until 2004 no same-sex couples in the United States had the right to marry in any state and until the U.S. Supreme Court’s 2015 decision in Obergefell v. Hodges the right was unavailable to same-sex couples nationwide. Due to this longstanding denial of the right to marry, most same-sex relationships appear artificially short when measured solely by reference to the couple’s civil marriage date. This circumstance has important legal consequences for many same-sex couples, as a number of rights associated with marriage are tied not merely to the fact of marriage, but also to its length measured either in absolute terms or relative to a legally significant event. These rights include social security benefits, immigration rights, the marital communications privilege, and the rights to division of property and awards of alimony on divorce. Moreover, a same-sex couple whose relationship ended before the legalization of same-sex marriage may not receive any rights associated with marriage. This Article is the first to explore the phenomenon of backdating marriages as a means to ensure that same-sex couples are made whole for the harms caused by their longstanding inability to legally marry. The Article demonstrates that the Obergefell decision applies not merely prospectively but also retroactively, and that same-sex couples have a constitutional right to have their marriages backdated to the date they would have married but for the existence of a legal barrier. Because such backdating can create significant short-term administrative challenges, the Article provides alternatives to actual backdating that are somewhat easier for government agencies to administer but that still provide same-sex couples with constitutionally mandated “make whole” relief. Administrative challenges notwithstanding, the Article concludes that actual backdating—or its functional equivalent—is constitutionally necessary to remedy constitutional harms to same-sex couples imposed by the preexisting discriminatory scheme.