A second or later marriage comes with some risks if either party to the marriage was not thorough in the legality of a previous divorce. There are several reasons that a divorce may be invalidated; in one case highlighted by the Social Security Administration, a possibly invalid divorce could have risked the wife's ability to claim benefits through her husband's earnings record.
In the case in question, the husband and his first wife both lived in Florida. The husband obtained a divorce from his first wife in 1935 by personally appearing at a proceeding in another country for the divorce. According to the document provided by the SSA, if that divorce were contested in a timely manner by the first wife, it might have been invalidated by a Florida court because neither of the individuals were living in the other country at the time the divorce was granted.
The husband later married another woman and, years later, she filed for benefits through his SSA earnings. In order to obtain those earnings, a spouse must meet certain requirements -- the obvious of which is a legal marriage to the earner. If a previous divorce was invalid, then the second marriage may not be valid either.
Because no one ever contested the divorce in this case, and the first wife went on with life for many years acting as if she was divorced, then the SSA ruled that the second wife qualified for benefits. Although this case ended well, putting your future happiness or stability at risk by ignoring the legalities of divorce is a big gamble. An invalid divorce contested by a qualifying party could throw all your plans and current relationships into chaos.
Source: Social Security Administration, "Effects of Invalid Divorce Where Parties Are Estopped to Deny its Validity" Oct. 22, 2014