Lingering Effects (my fault or not??)

Hi. I broke up with my ex boyfriend a year or two ago. This post will contain references to Dissociative Identity Disorder which I believe I have and am seeking treatment for, currently(if you don't know what it is, look it up, it's got a decent role in the 'story'). Trigger warning for light implications of sexual themes.

I knew my ex for about 7 years. Our relationship did not start out well. It was a long distance one, and it started out via us doing risque things that I did not really reject, but was mildly uncomfortable with. After a few weeks, I discovered he was with another girl at the same time as me. I eventually ran her off after what I can only assume is several months. Mental illness makes time frames blur. Afterword he went into a severe depression for a week or two and didn't want to talk to me. I began having severe flashbacks that basically incapacitated me from doing anything, including at school. I was a mess.

After he got over that episode, he came back to me and said he didn't care about her anymore. I did 'nag' him for several months afterword due to the pain it inflicted on me mentally. This is when my identities began to reveal themselves one by one. He became particularly attached to a main identity of mine and treated them like a second partner. This didn't bother me in the slightest, it was "me" (the way I understood it then). I continued on with my insecurities, trying to press them down as he was saying it was bothering him at this point.

A while later, he revealed to one of my identities that he was cheating on me. Again. The identity alerted me and I flew off the deep end and kept asking him why, why, why, why, ect. I don't remember a ton of it, but I know he told me that I was not being affectionate enough so he sought it from someone else. I broke down for several weeks to a few months and began 'nagging' again about who it was, how much it hurt me, ect ect. My identities became more prominent and they began taking my place a lot more. From what they've shared with me, I know they roleplayed with him a lot on games and otherwise. He became attached to all of them and another one became his basic 'third partner'.

Fast forward a bit past the parts I don't entirely remember and he was getting on once a month / every few months. He blamed it on school, yet he would be on a game constantly after school. I had cut him off from 'satisfying' media, if you get my dift, and risque anime he enjoyed watching (though I let up on the anime a bit toward the end). One of my identities took to 'scouting' to see if he was up to anything on the game. Unbeknowest to me, he was still with the last girl. He admitted it, finally, and I totally broke down and told him it was okay, and would even occasionally ask him if she was doing okay. He never talked about her, but to say that she gave him emotional support when I was 'hurting him' by coming after him with the cheating things. After quite a while I finally said that enough was enough. I / my personality told him that we were done and we were breaking up. He said he was relieved. We slowly faded out of contact with him and no longer speak to him.

A year later, I get on that one game again and he's left us a message. He tells me that I'm at fault and I put him through 'three years of hell' and that he hates me now, but loves one of my identities he treated as a partner (who didn't 'nag' him about infidelity) and that they were the best 'bro' he ever had. As for me, he absolutely refused to talk to me because I was 'abusive and wouldn't let it go'.

Was I abusive? Were my responses incorrect? This has bothered me for so many years and contributes so much to my depression, PTSD-eqsue symptoms and DID. My childhood was not that great, full of abuse itself, so I am unable to identify if I am abusive, if he was, or if this was all just a huge mess I should have just left while I had the chance. I can convince myself it wasn't my fault for only about a day before I just fall back into "I'm abusive and just excusing my actions".
I can't really think about the first girl's name without throwing another identity out or fully breaking down with flashbacks involved.

Sorry if this breaks any forum rules. Sorry for posting this. Idk, sorry in general.