Regardless of one's position on gay rights, every thinking being has to admit that married people need to have a place to get divorced when their marriage falls apart and they meet the standards for divorce in their home state.
If they were legally married somewhere, and move to a state that does not allow gay marriage, you can't just leave them in limbo when the relationship falls apart because you don't like how or when they married.
For 48+ years, California has allowed heterosexual couples to get divorced so they can move on to other bad relationships, or marriages. As many comics and some politicians have commented, gays deserve the same privilege of getting into another bad marriage as straights.
Well, it still goes on in some jurisdictions that judges are so entrenched in the concept that gay marriage is wrong, that they insist that gays who are married must stay married, even if they aren't "gay". [I didn't expect you to follow that, but those are the facts]
In Arizona, it took 3 appellate justices to fix a problem, with bizarre wrinkles. A couple got married in Hawaii. They later moved to Arizona. When they wanted to get a divorce, the trial judge wouldn't allow it because the husband had started life as a woman. He had undergone gender re-assignment surgery and hormone replacements, and along the way, had sufficiently changed his gender that the State of Hawaii issued him a driver's license and reissued his birth certificate to reflect he was a male. OK, some people think that's weird, etc., but that's not the point.
The trial judge concluded he wasn't man enough to be married to his wife, or at least he couldn't provide enough proof that he was a male, so no divorce. Even his wife agreed they should get divorced. Well, now they can, at least in Arizona.
Get a grip, people. Life goes on, like it or not.