Nothing wrong with that. It’s better than being awkward.

Being on good terms with exes is perfectly fine and doable. Plenty of people are on good terms with exes. It’s way better than being enemies.

I am not entirely sure about being actual friends though. We might have different definitions of friendship. Friends are invited to your home and you introduce them to your significant others and your family, and you talk to them and see them etc If you can’t really do that, especially if you can’t introduce them to your next significant other, and he won’t invite you to meet whoever he is dating, then it’s not actual friendship but more of a being on “good terms” or acquittances you are friendly with. You also have to consider your soon to be ex’s boundaries. He seems to have none. Especially because he is often intoxicated. So I’d be careful (he talked to your other ex about porn habits, I’d not be surprised if he talk stupid stuff to someone you might date in the future). Perhaps being polite and cordial is a better idea than real friendship

So I think you are referring to being “friendly”, rather than being “friends”.