my boyfriend (24m) ended things with me (22f) after reading messages between me and a male friend- very long post

i (22f) have been with my boyfriend (24m), and our relationship has had quite a lot of history.
earlier in our relationship, he cheated on me. i chose to forgive him and stay because i loved him and genuinely believed we could rebuild the relationship. to be fair to him, after that happened he did make changes and followed through on a lot of the things he promised me.
however, i don’t think i ever fully recovered from being cheated on. i compared myself to the other girl constantly and eventually realised i’d built up resentment, even though when he asked me whether i resented him, i told him i didn’t. i know that was wrong of me and i should have been honest about how much i was still struggling.
we’ve also had recurring issues with conflict and communication. when he’s upset, he has hung up on me, withdrawn for days or physically left during arguments. i’ve told him that being suddenly cut off like that really affects me and makes me feel abandoned. at the same time, he has often felt that i don’t understand him properly and that he shouldn’t have to repeatedly explain how he wants to be treated.
the situation that ultimately ended our relationship involved a male friend of mine.
my boyfriend saw an instagram notification from this friend and ended up seeing our messages. my friend had also been cheated on, so we’d spoken about that shared experience. he was mainly talking about what he was going through, and i listened, comforted him and gave him advice based on my own experience. for example, i told him that if he genuinely felt in his heart that he wanted to forgive his partner, he could, but that he shouldn’t allow resentment to build.

i also brought up the fact that he “hadn’t been a saint himself,” referring to things he’d previously done. i regret doing that because regardless of our history, he was entitled to tell me that something i’d done had hurt him without me immediately bringing up his mistakes.

he ultimately ended the relationship over the situation. i’m trying to take accountability rather than convincing myself i did absolutely nothing wrong. i can recognise that i should have considered his perspective more carefully, and i regret becoming defensive when he expressed his hurt. i’d really appreciate neutral outside perspectives rather than just being told either of us is completely right or wrong.