How do I get over it?

Hey ladies, I could really use some advice. I was in a relationship for a year and three months with a guy I have known since 2017. In January we decided to break up because we don’t live in the same city so it was hard to see each other, and there were some issues I had to work through with my child’s father. When we initially broke up I made it know that I wasn’t interested in pursuing anyone else or having sex with anyone other than him. His response was almost always “well I don’t want to limit your happiness.” Anywho, throughout our “breakup” he was constantly blowing up my phone telling me he missed me, wanted to see me, and how he couldn’t stop watching the adult videos we made. But anytime I brought up being sexually involved he would shoot me down and say it wasn’t a good idea. At this point my gut was telling me he was having sex with someone else so I would bring it up jokingly but he was never straight forward with his answer. Fast forward to last night he mentioned to me that he wanted to try our relationship again and that the past is the past and should stay there then admitted to me that he had been sleeping with someone else and it happened about three weeks after our breakup. I know I can’t be mad at him because we weren’t together but my heart still hurts. I feel disposable, like he did what he did then decided when the fun was over that he wanted to come back to me. I told him that the trust was broken and that I need time to process what I now know. Because I’ve always been the “if you touch someone else break up or not I no longer want you” type of person. He basically told me I needed to get over it because it happened and there was nothing either of us could do to change that. I know he’s right but I’m still hurt, and shocked by the situation. The person he had sex with lives in the same town as him, and until this past weekend they were still communicating. So I have alot of anxiety about this whole thing. Does anyone have any advice on how to proceed with this situation. I care so much about him but I don’t think this is something I can easily get over despite knowing I shouldn’t feel the way I do because we weren’t (and still aren’t) together. Please help. 🥺