TW mentions of sex, cheating,  TLDR at bottom

I need to figure out what I am going to say and do with this man by Wednesday night. 


note: I know I need to leave my current partner because of how he is and I have he just does not take me seriously or even try and get a job to move out and I'm empathetic and dont want to kick him out he also gives me slivers of hope to when our relationship was goos and we where happy

context: been with the same person for 2 years , the last year has been mentally and emotionally abusive , i believe I am trauma bonded to him. He's cheated on me multiple times and cries and says self sabotaging,  I want to forgive him and as someone with BPD and I know its stupid now


6 months ago in my worst depression , worst time in my relationship and the fighting was at its worst. I was volunteering I was trying to get myself together and away from him and I had gone into a fast food place to get food and a younger worker saw me and I saw him I don't know what it was we didn't talk but it was an instant attraction that day. My family member and friend even commented that he was "tripping" over me. I liked the attention I wasn't getting any from my partner, I made it routine to see him, we eventually talked and would say hi to eachother. After 2 months he randomly added me on Facebook saying I just popped up but that wasn't true, someone had him hold their phone for a second with my facebook open. I should have known from this that he wanted more, he was attracted to me but I'm stupid.

We talked about work, our partners , life , ect . I'd never cheat on my boyfriend and what he did to me killed me I wouldn't do that to him. I did tell my friend I thought he was cute but that was it well my ex went through my phone which I don't care I had nothing to hide and I apoligized for calling him cute but that he was just a friend nothing more and that he would never like me anyway. (I'm very insecure even more so because of my relationship) 
We had a huge fight and went to bed the next day i figured I could go through my partners phone and caught him cheating for the past month. We had another huge blow up and seperated for a week he slept on the couch for a week.
We ended up somewhat making up but its been on n off rocky for 3 months.
The other guy had stopped talking to me for a month and came back apologetic because of life happening and it was out of his control I understood honesty if you knew why you'd get it too (Hospital stays) and I talked like normal friends, even best friends till the beginning of this month. He asked me to go on a drive with him 3 days in a row , we talked we flirted , he'd flirt with me on text a bit but not like those nights.
We ended up sleeping together in the back of his car, I cried after he kissed me and rubbed my head told me no matter what he cares for me, its okay, he was the sweetest person i had ever been with. We laid in the back of his car before he dressed me and held my hand all the way home. He never has stopped texting me calling me baby and all sorts of things. He's been nothing but sweet even treats me like a girlfriend but heres the kicker

We both cheated on someone but we both don't know if we want to be with those people. I don't know what to do I invited him out wednesday night to talk  and i thought i had what I wanted to say and do figured out but I dont. I'm so confused and lost part of me says cut ties because this isnt right and okay and I can't go back to being just friends I'm just not that person but at the same time i sont want to lose him forever? But also am I falling into toxic BPD shit ans ways to cope with my shitty relationship? We've connected through normal talking the last few months but I really don't know what to do..I really need outside advice n eyes on how to handle this??


TLDR; my partners abusive and I slept with my bestfriend who is dating someone and now we act like we are dating and i don't know what to do and i see him on Wednesday night