Evidence from The New York Times that backers of gay marriage, of which the Times has been a leading advocate, sense that victory has been assured:
1. Dan Savage tells us in a recent NYT Magazine cover story that hey, married gay couples may not be faithful to their marriage vows, and not only is that okay, but redefining the marriage ideal to accomodate creative infidelity might be just what straight couples need to spice up their lives.
2. In today’s paper, Frank Bruni and Cynthia Nixon say that hey, despite what you’ve heard, some gays really aren’t born that way, but rather choose to be that way — and the only people who care about such things are bigots.



JonF
I suspect that the “particular subset” you mention is probably young(ish) and good-looking.
Actually, it’s pretty varied and not as dependent on looks as you might think. It really has more to do with the individual than anything else, but there are plenty of men who are very active into their 50s. And there are plenty of young guys who want nothing more than to settle down in a monogamous relationship.
Looks aren’t much of a predictor either. You’re right that gay culture can be very shallow when it comes to what’s attractive (men tend to be generally). But I’ve known some who were very attractive and self confident and settled into long term monogamous relationships and others who were handsome as all getout, but insecure about their looks and would end up doing things like porn and escorting as much for the sense of validation they got as anything else.
The worst offenders and the people I really had in mind were those who are hooked on meth. It’s generally used because it both throws the libido into overdrive and completely tosses inhibitions out the window. I’d say a large number of the most promiscuous guys out there these days are under the influence.