My $0.02 Worth
I was married in a church ceremony. I know others who were married before civil authorities. They're both valid marriages. The way I see it much of the homophobic attitudes against same sex marriage has more to do with control. In my mind, discrimination is wrong for ANY reason.
In the Old Testament there were nothing instituted as to how many many wives a man could have. Jacob had two wives. There's the matter of concubines of which Solomon had over 700 of them. Abraham had concubines also. King David's statement after Jonathan's death that "your love to me was more wonderful than the love of women suggests that their relationship was more than friendship.
Some observations: it's said that same-sex couples do not procreate. There are heterosexual couples who, for various reasons, cannot procreate either. My spouse couldn't produce a child. Same sex couples are prohibited from adopting children and yet I don't see many heterosexual couples knocking down the doors of the adoptions to give these children a home. If our opponents are so concern about marriage, then why don't they help out those couples who are struggling? To me, their argument doesn't hold water.
A bible based marriage, in my mind, is one based on love, commitment and respect for each other. I think a lot about about marriage is suppose to be is based on a patriarchal model of men having control over women. I totally disagree with this. I believe that feminism came about because of this attitude. Looking back I'm glad it did happen.