Having an opinion of what marriage should be does not make someone a bigot. Some people are way too quick to pull out the racist/bigot/homophobe card because they hear an opinion differing from their own. As others have said, in 100 years no one will give the idea of same sex marriage a second thought. The institution of marriage wont crumble, society will not fall apart at the seams (at least not for that reason). New paradigms take time to get used to, forcing them when society is not ready for it is problematic.
I personally, shockingly, am for gay marriage. But my life does not hinge on it. Wont stop me from building a life with whom I want how I want.