Why am I repulsed by gay promiscuity?

If you value stability more than ual satisfaction then your values are going to clash with his, it's okay. It's like when you take one of those silly internet quizzes and it asks you to choose between things and put them in the order from most important to least.. and your lists are different. There's pros and cons to each choice. Perhaps if you can see the pros of his choice then it might be easier to detach emotionally from it (it doesn't mean you have to approve of it or ignore the cons, it's more about finding a balance and feel less strongly about it). His choice doesn't fit your needs and it's understandable that it would cause a reaction of repulsion in you, even if you don't need him to fill your needs. I think it's one of those human things. Like others have said, I'd also try to get to know more gay men to balance out the impressions you get.