0,96% of straight couples end their marriage before two years, opposed to 0,59% homosexual ones.
2005 saw no homo divorces, 2006 had 3 and 2007 has already 17 (and I know one)
When the gay marriage law was passed in Spain in 2005 (which is not a specific gay marriage law but "regular" marriage open regardless of sex) we all giggled a little bit because it was passed right after the "express divorce" law.
Until 2005, divorce was a pain in the ass. There had to be a "guilty" person, a "reason" and you even had to wait 2 years to get it "just to have enough time to rethink". Now it's simple: you want a divorce? have you agreed on terms? Done.
However, it's remarkable that gays are divorcing less than straights. Reasons for that? I guess that because gay couples are marrying less (less social pressure). But I guess there's more behind. And I read somewhere that "new families" (monoparental, homosexual, polyamorous...) will be the ones that will sustain the "family as nucleus of society" concept.