In my country is same-sex marriage legal since 2001 (as first county in the world, if I have to believe Wikipedia), and I honestly find it a very good idea (and policy) to have the possiblity to marry with the person whom one loves the most (without any judicial exceptions on sex/religion/gender preferences/etnics etc.).

Although, I must admit, at the same time you see an devaluation of the concept of 'marriage' in my country. And I mean this in the way that the general/popular opinion towards traditional relationships and marriage is shifiting from positive to a more negative attitude in my country. On top of that there is a declining number of marriages in my country for the last 10 or so years (negative trend, but research indicates that this is mainly because of economical reasons).

So I can understand the argument that legalizing same-sex marriage can influence your county/society, but that shouldn't (imho) stop people to marry with whom they love the most.