You can be horny to get off and not attracted to someone. It doesn't make you gay (not that there's anything wrong with being gay). I love ass sex with women and it doesn't feel the same, I agree. Cheers.

You are friends with benefits. Don't overthink it. It works for you. As you said, a mouth's a mouth, and obviously a bum's a bum.

If you had a relationship with that dynamic with a woman, would you consider it part of your sexuality?

You don't need to fit any particular label, but you could consider whether "bisexual and heteroromantic" resonates with you.

Still, even as a gay man, not all of my sexual relationships are romantic. It's okay for sexuality and romance to be separate at times!

Don't worry about the labels, enjoy it for what it is for you.

Check out the different ancient Greek variations of love. Also don't worry so much about what it means. We all focus on defining things too much.