Discarded then taken back then discarded again

The cycle is agonizing. He discarded me after he found some messages in my phone. I’d been entertaining other men randomly (nothing but texts) to feel some kind of happiness and regain my power after being emotionally abused for so long. I was gaslit, manipulated, and treated like dog shit for years. He left me and moved out. It was rough and i felt like my world was crumbling. He came back crying and sobbing and telling me how he needed me and apologizing, as well as asking for me to find us a therapist. Just to go through my phone again a week later and tell me he can’t trust me and I’m not telling him the truth. I don’t even know what he thinks he saw and he won’t tell me? He just kept saying “you know what you did”. Which is basically the sum of all of our arguments. I haven’t done anything wrong since the initial go around. I’m so lost.