Most people cannot fathom the idea of self sacrifice.
Absolutely true. "Why should I sacrifice what I have? Why can't YOU?" or some other ridiculous accusation follows.
I've wondered - why do gays want to get married (in American terms)? The institution of marriage in America is a fucking joke; do they really think that they'll do better than straight people? I doubt it. The divorce rate is nearly (or at) 50% for straight couples in the USA. I don't think most gays are more adept at avoiding this pitfall as most straight people.
The problem is, there is no conservative precedent (as you pointed out scourge), so traditionalist viewpoints can't apply here. Even a moderately conservative viewpoint (ie - I don't care if gays get married because I'm not gay, it doesn't apply to me) doesn't work here, as many liberals (being the purveyors of ad hominem as they are) would shun this viewpoint and call one a homophobe.
As a side note - I'll provide an insider perspective here. Gay marriage has already become legal in several states. One of my relatives was recently married to a woman she has had a relationship with for around 4-5 years. If this was a man/woman relationship, this could be viewed as ideal; date a long time, live together, get to know each other, and then tie the knot when you have stable careers and a roof over your head (which they both do). As far as I know, they are not planning on having children. I attended this service, and while I was initially ambivalent (and still am, in a lot of ways), there really seemed to be a genuine love and respect between the both of them. Especially when they read each other their vows. I cannot say that I wish them anything less than the best.
I suppose my statements here may be little more than rambling, but I will conclude by saying that a homosexual household like what was outlined above would be stable, moreso than many heterosexual households. Perhaps it comes down to the person, not the sexual orientation? Yeah, we'll go with that.