Hey there, just another person with bpd dealing with jealousy. Any solutions or coping mechanisms??

I'm 23/F and have been dating my current boyfriend for 7 months. He gives constant reassurance and is the man I want to marry. He has also said similar things to me. So I'm a bit confused on why I am so jealous of his ex. They lived together and he currently lives where they did (but she moved out). Doesn't talk to her aside from getting rent each month. Doesn't follow her on any social media once I asked him if he could unfollow. She asked to hang out with him once and he said no. So wtf lol

I think the jealousy really began when I noticed his old profile picture of them together was still up on facebook. It'd been changed, but the old picture was still up as a past pfp. I never had anyone use me as a profile pic and when he made me his facebook profile pic, I honestly just felt like a replacement. Like "ooo look, both girls he dated side-by-side." Grossed me out. He has since deleted it but I can't get over all the small things. I also still find her old hair in his bathroom. I know it's old and he isn't cheating, because she used to dye it this really ugly color (his words lol) and now her hair isn't dyed.

I go through episodes of checking her insta. I think I'm just really possessive. I know I'm prettier and she treated him horribly (called him fat and started arguments at the drop of a hat), but I can't get over that they used to date, he was the one broken up with and he still lives there. Plus we started dating only about 2 months after they broke up. Surprisingly, I'm not jealous of any of his other ex's, just the most recent. I also watched her insta stories saved on her account through a burner account (like a psycho stalker) and she has a lot of similar hobbies as me. It honestly just pisses me off. Some of his family members are friends with her on facebook as well and it drives me insane.

I know it's completely stupid and all this stuff means nothing and it's just my brain working on overdrive. Maybe I just can't let myself be happy? But I can't get over it and it's driving me insane. I know if I bring it up anymore, it'll wear him down, so I've just been suffering in silence like a good noodle. But I feel intensely upset and jealous at random times/days/weeks and I feel like I'm going to combust. So, please, if anyone has advice on how to minimize this, please let me know. I tried blocking her accounts but I always just go back and unblock them. I feel officially psycho.