I am gay. I have been in a very stable, loving relationship with the same man for just over 12 years. And guess what? I don't support "marriage" for gays and lesbians.
Why? Well, as I always say, straight people have been getting married for several thousand years and they still cannot get it right -- why should we buy into that? Do I agree with equal legal rights for gay and lesbian couples? Absolutely. But I want it to be called something else.
The whole concept of marriage is abysmal to me. Marriage started, after all, as a transfer of property (the woman) from father to husband. To this day I do not understand women buying into this -- and don't get me started on the waste of money on weddings! Criticize Hallmark for creating holidays to sell cards; but the wedding industry is way worse for encouraging the lavish waste of (probably) billions of dollars.
Okay, all that said, I want to direct you to this article.
While I do not support the idea of "marriage" I am deeply and sincerely touched by those heterosexual couples who are showing solidarity to gays and lesbians. And this is not a new trend. I actually know people who have said the same thing to me.
Me, personally, I do not support discrimination of any kind -- even if I do not agree with the thing being discriminated against.