Do i (16 F) break up with my boyfriend (16 M) of 7 months?

This is a long, long post and i have never posted on here before and i just logged in to this account again so i can get some advice. also, i dont know which subreddit i should post this to.

Me and my boyfriend’s relationship has been rocky from the start. He had his fair share of an unpleasant reputation. Cheating scandals and such around school. Within out first few months of dating (like 3-5) things were smooth until April where i fucked up and gotten drunk and one of my friends (lets call her M, F 16) i was with at that time told me i kissed and did some other stuff with another friend (lets call her E, who is also F 16). (It was only 3 of us in that house). But, i had my doubts on that story bc M and E would make rumors about people, so i heavily doubted that what i did was true. My boyfriend picked me up at M’s house, and M told him what happened. Of course, i couldn’t tell him what really happened bc i was black out drunk. i really couldn’t get home. So, he was mad, he wasn’t taking my side in this situation and i accepted it fully that i was in complete fault here. to this day, i have no recollection of what really happened. Additionally, i have not spoken to M. (E doesn’t remember anything either, we dont really talk anymore because of this situation).

Present day, we’re past that situation, and every time it came up, i always acknowledged my fault in it. Now, my boyfriend (L) has always had issues with trust in a relationship. He had access to my social media accounts and such. I had nothing to hide from him. I was pretty insecure and anxious at the same time, (I was diagnosed with BPD, but i think it was a misdiagnosis.. so i dont know bc im aware that drs don’t diagnose teenagers with that disorder.) so it contributed to the fact that i wasnt stable either. I also hold his social media accounts. I have always been sorta mentally unstable. School started this June, we weren’t in the same class, which lead me to start overthinking. I didnt mention it to him bc all the while i was at home after school, he was out with his friends, specifically K (F 16). K and I had a pretty okay relationship. Me, her and E were pretty close a few years ago but we stopped talking. So, K and L started getting close. One of their friends invited them to drink. They got drunk, thats all i know. That was probably a week ago. Now, just a few hours earlier, K messaged me saying that her and L have been dirty talking and that they even kissed and L gave K a hickey. I am distraught. I felt ruined. I felt all the effort i gave to build this relationship up went crumbling down. K even told me and showed me screenshots of them talking on tiktok (the one acc i dont hold on L) A WEEK AFTER THE WHOLE SITUATION. K knows what she did. L accepts he did it, but points it back on K. In the conversation, they were talking about sex, talking about the condom I BOUGHT FOR ME AND L, TALKING ABOUT BEING ‘lovers in private’. L told me he was just giving the energy K gave. I would understand if this was a drunken thing, but theyve been talking even AFTER everything happened. what the hell. Currently, as im writing this, L has been spamming my phone, and im not responding. i feel like im going insane and im loosing myself. what do i do?

(im sorry, i dont know how reddit works, and i dont know how TLDR’s work.)