Should i believe him?

alright i need your help. I am a ‘28F’ and need advice on if i should try to make things work with my ‘29M’ boyfriend of 6 years. Last year he decided he wanted to enroll in acting school and pursue his long awaited dream of being an actor (Keep in mind we live together) and started going to classes. During his first year he introduced me to all of his new acting friends, and all was going well! (except that he would have like full on sex scenes with people in class, but would get mad at me if i was in the same room as boys i’ve dated or even kissed lol)

however, when he started his second year in school i noticed that he immediately stopped bringing me around his new set of friends (the groups change) and i noticed right away that he was acting weird. He stopped inviting me out with them completely and was being secretive about this new group. Because women have excellent intuition i assumed he was having an affair.

These assumptions turned into snooping (which i am not proud of) and i looked on his Venmo and he was sending drink requests back and fourth from a girls name i didn’t recognize. immediately i found her profile and she was in his class! i confronted him about it and he said that he was out with all of them in a group and it wasn’t 1x1.

But i was detrimental in finding out what was going on, so i looked through his phone (again not proud of this) and there was TONS of messages of him talking about his feelings towards her, and her sending suggestive messages and confessing her feelings for him. Keep in mind this is when i was confronting him about my suspicions.

I end up confronting him and he tells me that he doesn’t like her back and he was trying to let her down easy, and that he didn’t want to offend her because he didn’t want drama in his school (lol it’s literally called drama class but OKAY) but honestly i just don’t buy it. I message her. She tells me that the feelings were mutual, but doesn’t provide any evidence and she said they were “working it out” because acting class is “intimate” (PUHLEASEEEE) so now i’m fuming but of course I decide to stay with him as long as he stops talking to her which he agreed too.

Fast forward months later and I end up breaking it off because i need space to deal with all of this and process and just can’t live together while i do that so i ask him to move out and we break up. After a couple months apart we start talking again, and he ends up kissing me one day when I am dropping off our dog (joint custody) and we end up trying to make things work again. 2 weeks later I am cleaning up his apartment and I find a letter from this girl, hand written, saying how happy she is to be in his life again. She even bought him this like custom artwork to go in his new apartment and everything. AGAIN i confront him and he says “i thought i threw that out, she’s such a psycho she won’t leave me alone” but how do you actively receive a gift and then bring it home and just not throw it out right away? also shouldn’t he not be talking to her anymore? it was mixed in with all of his other artwork and gifts. so clearly it was placed with them to keep.

His excuse for being friends again was that she told the director she didn’t feel comfortable with him being in a certain class that he wanted to be in so he had to make amends.

I am at a loss. I still love him and WANT to believe him, but these actions are pointing in the direction of no return. I left his apartment and told him I can’t keep doing this anymore. He hasn’t texted me at all since (insane).

What should I do?? Am I the Asshole and should believe him?