There is much discussion that could be had on your last comment, Mojo. In fact, I am sure there will be. I might reply to more of it later, but for now I wanted to address this:
I would step back and ask this: what is sex? As I understand it, a penis entering a vagina is sex. As such, I do not believe homosexual acts constitute sex. That said, I am not saying this definitively; I could be proven wrong. However, Zec Austin's point is quite on target though, a male lying with a male is an abomination and punishable by death in Law; therefore, even if it were considered "sex", it is unacceptable and not marriage in God's eyes. For reference:
Leviticus 18:22 You shall not lie with a male as one lies with a female; it is an abomination.
Leviticus 20:13 If there is a man who lies with a male as those who lie with a woman, both of them have committed a detestable act; they shall surely be put to death. Their bloodguiltiness is upon them.
I do want to second what Zec said, the "one flesh" relationship is not exclusive, it is simply saying a man is "one flesh", uniquely, with each of his wives. That said, they are each part of his family, and therefore they could all be called one just as the church is called one.