You damn fool. This is not about two people who love each other. This is about the fabric of our society.
Marriage as recognized by the state is to support the now thousands-year-old concept that the nuclear family -- 1 mother, 1 father and children -- is the best way to raise children into well-adjusted adults. The state has a compelling interest to promote this for the good of the entire country. Even if some people don't have kids and other divorce too quickly, the underlying principle still represents everyone's best interests. If Marriage is merely a legal contract that can be redefined at a whim, thus cutting the cord to the underlying interest then it has no meaning at all!!!
Once you remove the basis, then it doesn't matter who gets "married" or why. If "love" is the basis, then every aspect of marriage is up for grabs. If gender is arbitrary, so is number, familial relationship, species, etc.
You might as well get rid of any laws related to marriage, since they have no meaning anymore -- it is all open for debate. No more tax benefits, no more estate planning (except perhas for progeny). The fabric upon which we BUILT this society is torn asunder. I shudder to think what the next generation will face -- no commitment, kids who are born into groups who may or may not care for them, artificial insemination to create kids for father-father-father-grandmother "marriages."
God help you all.