What an excellent article. Well-thought-out, and written based on the view of marriage as a secular, and faith-based, and love-based affirmation.
I'm not sure what to add other than these thoughts:
Marriage in our society clearly goes beyond faith, as it has legal implications as well (i.e. making important health decisions for your spouse if his/her life is at stake, transmission of property/assets if one loses one's spouse, etc.). As such, this is a human rights issue now, not just a religious one.
Also: I refuse to believe that my parents' marriage, with my father's physical and emotional abuse toward my mother, should be considered more "legitimate" than a loving, trusting, nonviolent relationship between two people of the same sex.
So yeah, probably the best article I've read thus far on this subject.