Would you feel disrespected?

My boyfriend is great. We're going on 3 years and we live together while we finish up our last year of college.

My boyfriend has a workout partner he met at the gym who is a grad student of around the same fitness level as my bf so they lift together nearly everyday. I don't like his lifting partner. At all. It's one thing to be a huge flirt but this kid hits on everything with a vagina and a pulse, has cheated on his gf, slept with married women, etc and it bothers me because my boyfriend told me he has tried to get him to hit on girls with him, or act as his wingman which my boyfriend has refused. I've tolerated this because whatever, they see each other for 2 hours 5 days a week just so my bf can have a decent spotter at the gym. The guy may be a dick and not respect relationships but it's not like they're great friends. Now this kid starts asking my bf for rides everywhere (he can't drive here because he is from another country) and hanging out outside of the gym and invites my boyfriend to come visit him in Jamaica (where he's from) for free. So they start hanging out a lot more and my bf has told me his friend literally tells him to cheat on me all the time. So I'm not mad at this kid anymore I'm mad at my boyfriend because I feel it's straight up disrespectful to have someone like that in your life who is so toxic. I 100% trust my bf not to cheat on me, but I really don't like that he has friends who try to get him to.

I have antisocial personality disorder (the proper medical way to refer to a psychopath) I'm not violent or anything but I'm a control freak and a big manipulator. So I've started trying to weasel my way in and break up their friendship form the inside rather than tell my bf he can't have certain friends. I've made a few fake tinder profiles and matched with the kid and convinced him to leave the gym early to have sex with these non existent girls while he's working out with my boyfriend so my bf gets pretty pissed at him because he's not taking the workouts seriously and keeps ditching him. I've also kinda manipulated my boyfriend too by telling him he can't think for himself and just follows people blindly like a sheep (which hits a nerve because he likes to think he's an alpha male).

I know I shouldn't be doing this, trust me you don't have to call me a manipulative bitch, I hear enough from my psychologist that I need better ways of dealing with things that upset me, but as of right now this is how I do it. I tried to be an adult and come out and tell my bf I had an issue with him because he was disrespecting me but he was all "I would never cheat on you, so it doesn't matter if someone tells me to, I have my own brain and can make my own decisions." And "what do you want me to do? Tell him 'hey man my girlfriend says we can't hang out anymore.'" And make me feel like I'm being a controlling bitch telling him who he can and cannot be friends with. Idk I feel like it's valid for me to be mad at my bf but I don't know how to come to a decent outcome without seeming like a giant twat. Should I put my foot down and tell him that I don't want him having this person as a friend or should I suck it up and let the friendship continue?