Well, take a look at the Western nations that have been trying same-sex unions for some time and see if you still think so.
A lot of people (of every persuasion) are more promiscuous when they're young, but settle down when they get more mature. One of my gay friends back home told me he stopped being promiscuous because he's gotten much closer to his partner, and the companionship and caring part of the relationship is much more important to him now. I met his partner, and it was clear there was a lot more to that relationship than the sexual part. (They've been together for three years.) I don't entirely understand it, and have trouble reconciling it with my Christian faith, but I am reluctant to condemn this relationship and ones like it.