The only reasons I see you mention are basically "b/c I wanna" and "it's not (measurably) hurting anyone" and they're consenting adults. You really haven't demonstrated, logically or otherwise, any real reason to turn marriage upside down to include homosexuals. Outside of govt benefits (SS, govt pension, etc..) there is no pressing financial reason either. Private companies are already setting up benefit plans that are homosexual friendly, from pension plans to medical benefits.
Your comment about your marriage vows are equally non-sequitur in nature. Not mentioning procreation in wedding vows doesn't change the original reason for why marriage was created in the first place. I was merely responding to the non issue about it "not harming anyone" as a reason for allowing something.