I'm so confused.

I'm in my late 20's, am 'officially' straight and have been dating and sleeping with girls for my whole life (I'm in a relationship with one now). I do consider myself primarily straight, but I have also slept with men over the past 10 years. I think maybe 6 or 7 in total, but they weren't anything spectacular, mainly because of my own nervousness or it just hurting too much (I'm a bottom).Most of the time when I fantasise about sex, it's about men with monster cocks having their way with me. For this reason, I've mostly slept with black guys (when I've actually gone through with it and met up with them and not chickened out). The thing is though, when I'm masturbating to these fantasises, as soon as I come, I'm disgusted with myself and the gay part of my brain just totally shuts off. During the day, when I see guys out on the street, I'm not attracted to any of them. I've never seen a guy and thought 'He's cute, I would love to sleep with him'. All I'm interested in are their cocks - I don't even like kissing guys. Also, when I'm with a guy, I generally feel uncomfortable and can't stop thinking about whether I'm making a mistake. It just doesn't feel right..Just today I was supposed to meet up with someone, but thinking about it got me so horny that I jerked off and then ended up cancelling the meeting because of how I felt after. I'd say I'm annoyed with myself for doing it, but I'm not. As soon as I came, I was instantly thinking about cancelling and was telling myself 'Good thing you jerked off because you didn't really want to go through with it, you were just really horny.'I'm so confused. Do I only want to have sex with guys when I'm really horny? Am I bi, or what? My solution to thinking about guys recently is to just jerk off and get rid of the feeling, but it always comes back.Has anyone else experienced/is experiencing something like this? I'd really appreciate some advice.