He cheated while we were exclusive, what should I do?

My boyfriend (24M) but also not my boyfriend cheated on me (F21) in the first 2 months of us being exclusive. So the way we started is this guy is my friend and he's a known player I knew that when we started this. One day he asked me to hang out with just us two instead of normal with our whole friend group, so that day we started exclusively being together. At first, it was us hooking up that's what I assumed so I didn't want to be exclusive with him, but he convinced me to (this is August 2024). This man started calling me every night about a week after we started this which made us grow closer emotionally. Like I said I knew this man was a player so I would tell him if you ever want to be with someone else just let me know and I'll be gone and good. Around November 2024 I felt a shift like "oh" I might genuinely like him a lot more than just for hooking up. In December 2024 we talked and he told me he also had feelings for me, but still, we don't date because we don't feel like we would work in the long run because of certain values (I can expand on), but we conclude that for right now we're both good with what we have. Mind you this whole time he was calling me every night, he rarely didn't call me, would tell me when he was hanging out with his friends and call me early to make sure we still talked, and if I was awake would call me after he came back home, we would hang out every once in a while get a sweet treat and talk for hours, if we ever got into a fight he would be mature about it and he wouldn't let me go to sleep with a heavy heart. I would talk to his siblings on the phone, in February I met his sister for the first time, I would go over to his house when his parents weren't home, we would play chess. It was going so well. Then in February 2025, I ran into an old friend we caught up and she told me about how she was talking to my guy. How they would hang out, study together, talk for hours, and were intimate once and she ended it with him after being intimate because she asked him what they were and he said that they were nothing and would never date. When she was telling me this I froze because she was talking like it was Fall 2024 and I hoped with everything in me that I was wrong and it was Fall 2023 but no i asked her and she said Fall 2024 specifically Sep-Oct 2024. The day I found out I told him to call me when he was free because he was busy that day and I ended it with a 32-second phone call because if I let him talk he probably would have convinced me to stay and I needed space. Now I want to give him a chance to explain because in my head he did it because he wasn't taking me seriously in the beginning but is now. But I also feel like I might just miss him since he was part of my routine for 6 months. Should I let him explain himself or keep my self-respect and move on?

tldr: Your friend-turned-exclusive partner, who has a history of being a "player," cheated on you within the first two months of your exclusive relationship (Sep-Oct 2024). Despite knowing his reputation, you grew emotionally close, and he expressed feelings for you, though you both agreed a long-term relationship wouldn't work due to differing values. In February 2025, you discovered he had been intimate with someone else during your exclusivity. You ended things abruptly but now wonder if you should let him explain, as you believe he may not have taken the relationship seriously at first but does now. You're torn between giving him a chance or prioritizing your self-respect and moving on.