Hate to tell you this but, not all of us are christians. Almost every culture there is has some type of marriage ritual. Just because christians have one of their own doesn't mean they get to write the rules for the entire earth. How can anyone say they have the right to tell two consenting adults that they can't publicly profess their love for one another? Beyond whatever dogmatic principles people live by, in a pluralistic society we should be able to accept that some people don't define love, family, and values the same as us. I don't want to sound like I am bashing christianity too much because I do keep a lot of christian values, but we need to be ok with people having different values form our own.
By the way, I do commend you for stating your argument. That took courage.