My ex gay boyfriend cheated on me with a woman I think…

My ex gay boyfriend cheated on me with a woman I think… He says no, but I'm feeling it, we've been together for 5 months, we always have arguments, I want to break up, but he won't let me and wants to try harder, the arguments are always because he disappears or gets weird on social media, but in person he's amazing, he went on a ski trip, I felt him different and started seeing his stories and stalking him until I found him in stories of people who were there with a girl, I saw them two days together! And I was already feeling, before he left, that something was going to happen! After that, he sent me a photo of him dancing on the tables and the girl was there, I called him immediately and asked who it was, he told me "what girl", after that, when he arrived, he sent me a message.

saying that he was confused about him because on the trip several of his friends were heterosexual and talked about the relationship and he couldn't talk about it because it wasn't open to him and that maybe he should be unhappy with someone he doesn't love to please his mother and prove something to his friends! I went to talk to him, about accepting him and I told him that I've been very patient with him for a long time, but I have my limits, every time he has a crisis he leaves me in a safe place, then he cried and asked me not to leave him and that he was going to see a psychologist and would tell his friends soon! I told him it was okay and that this was a process and that I wasn't going to force him into anything but I couldn't feel insecure and unloved every time he had a crisis! He was fine for three days, he called me super happy, I told him about his day and yesterday he called me to go to his house, he took me to dinner and then we did something (if you know what I mean) we took a shower and he said he wanted to separate because he thought he wasn't 100% for me and that he didn't think I deserved him and that he wanted to invest in him, that was midnight and we had done everything, it was a great day and he just changed, I wanted to know what you think and what is the likelihood of him going back? I don't think he's mentally well