obsessive compulsive thoughts about cheating/unfaithfulness?

Hello there. I'm not diagnosed with OCD, and I don't think I have it - but I was hoping to come here for advice because the way my brain is about this exhausting obsession is driving me insane. I need to know how people who struggle with unwanted intrusive anxieties that drive them to repeat certain behaviors cope and manage their brain.

I have this really bad habits of mentally prepping for potential signs of cheating/unfaithfulness in my relationship. I tend to rehearse conversations in my head, not just about this topic, but it could be any topic, and imagine what i would say in those scenarios. I have a lot of emotional baggage that I dig through in my head and think up situations in which the Bad Thing happens, or the Hard Conversation happens. But it bleeds into actual paranoia for me that compels me to try to soothe the anxieties through finding a sense of control. I routinely check my boyfriend's social media follows and nose around any girls he interacts with that look like she could be his type, analyze everything about their dynamics so I can look for signs. I don't talk to these girls, the most I've interacted with was one who was friends with his coworker and would give the two of them rides home - I glared at her once because I didn't like the way she was hovering around him and playfully teasing him. I know it's all super weird, I'm not proud of obsessing over this, and it hurts the trust in our relationship both ways. But I keep having these unwanted thoughts of what would happen if he did, what I would do, what my escape plan would be - but also how I can prevent that from happening by making myself as attractive to him as possible. None of it brings into question if he even would do such a thing. He has cheated on the past, but that was long before we knew each other and when he was in highschool. I don't imagine him as the same person he was then, it's clear he's grown up a lot.

I want it to stop, to be really freaking honest. I'm exhausted from worrying about something like that and it's been taking a huge toll on me. I don't want to control who he's friends with because that's not fair and I wouldn't want him doing that to me. But I also want to feel safe and secure and trust he wouldn't betray me in such a way. And also just not worry about crap like this unless there is a legitimate reason for me to suspect potential cheating. I don't want to be constantly looking out for it and ignore the rest of him and our relationship, which despite its imperfections - over all is a pretty good relationship.

Any advice welcome, but preferably from those who struggle with OCD in relationships/friendships.

Thinking about it too, these behaviors repeat themselves in different ways in my friendships too, and in other daily life moments.