Common law marriages can present particular problems for divorcing couples, particular when one spouse denies that a marriage happened. As one veteran Pennsylvania matrimonial lawyer says the problem with common-law marriage is not making it; it is unmaking it in a divorce.
Only 10 of the 50 states still permit new common law marriages within their borders, and five other have grandfathered the practice. Many states recognize common law marriages that were contracted in an alien jurisdiction that was the parties’ residence at the time of the marriage. In general this recognition only becomes a question in the event of divorce or sometimes when the survivor of a common law marriage that ended in death seeks survivor’s benefits. In other words, even states which no longer recognize new common law marriages must deal with them for divorcing couples who created them earlier in other jurisdictions.
Illinois, Minnesota and Arkansas do not recognize the claims of common law marriages of their own residents in foreign jurisdictions. A number of other states demand that their residents "demonstrate some minimum amount of contact with the common law state before the court will consider whether a common law marriage actually arose under that state’s law." At the extreme end is New York, which has taken a very generous view of claims of foreign common law marriages by New York residents.
This question of interstate recognition of common law marriages can create difficulties when residents of a non-common law state visit a common law marriage state without becoming a resident. Since people go about the business of life without being required to make a formal proof of the claim of marriage, a cohabiting couple may assume, incorrectly, that they have a valid marriage when in fact they do not. They may discover this only if they attempt to divorce. This problem can be very difficult, for example, for a woman who asserts a claim to a husband’s pension.
See also Palimony.