Even besides its anti-gay bigotry, the DOMA is an iffy law regardless.
Let's say Brittain33 here decides to move to, say, South Carolina. This state, through DOMA, doesn't recognize his marriage to another man. He could thus legally marry a woman there. Per the US Constitution, his home state would be forced to recognize his South Carolina marriage even though he already has a recognized marriage with his MA husband and polygamy is illegal. Confusing legal hellhole waiting to happen.
Why wouldn't South Carolina be forced to recognize the Massachusetts marriage sufficiently to deny this potential bigamist the right to marry a woman in South Carolina until the Massachusetts marriage was dissolved.
Indeed, under the full faith and credit clause, one could argue that if a same-sex couple moved to South Carolina, their marriage would instantly become null and void under South Carolina law and this under Massachusetts law. (South Carolina law explicitly calls for this at present if I'm understanding the meaning of the law latin they are using. [SC ST SEC 20-1-15])
Now if one husband moved by himself to South Carolina and the other husband remained in Massachusetts, that might cause a problem, but no more so than any other marriage case where a marriage would be valid in one State, but not the other. For example, in Massachusetts, it is legal for a man to marry his son's wife after his son's marriage has ended, but not in South Carolina. Granted, not a common case (and an odd one since both states prohibit a man from marrying his grandson's wife, his grandfather's wife, or his stepmother, so it probably is an unintentional omission from the Massachusetts law.)
More common would be that Massachusetts and South Carolina differ on the age at which one can marry, with Massachusetts allowing it earlier than South Carolina does, if there is parental consent. (One source gives an absolute minimum of 12 for females and 14 for males in Massachusetts, but if there are absolute lower limits it's not in the chapter of marriage laws that are available online for the commonwealth.)
In any case, there probably is applicable case law from the days before the
Loving v. Virginia decision that would adjudicate what happens in the case where one member of a marriage valid in a State moves to another State where that marriage is not valid and then enters into another marriage there.
