I think statistics will bear out that Gay men do NOT stay together for long periods of time. There are exceptions. I happen to know a gay couple who have been together for over 40 years. However, lesbians DO stay together. It's interesting.
If memory serves, five percent of gay men are in long-term relationships (20 years or more, I can't remember what the study said). This compares with heterosexuals, half of whom are in relationships of similar longevity.
I also know gay men who are in monogamous long-term relationships. One couple I know has little to do with 'mainstream' gay culture, because it is so unhealthy. They are very quiet and circumspect. (I've known them since grad school, 20 years.) Of course, I have trouble reconciling my understanding of the Scriptures with my friends' lifestyle, but I am willing to let them make their own moral choice -- we will all stand before God in the end.
Anyway, there's an old joke: Q: What do gay men bring to a second date? A: What second date! Q: What do lesbians bring to a second date? A: A U-Haul.