How do I let go?...

I met a guy back in June 2020 who pursued me hard. He began talking about marriage so early and we had so many deep conversations at the start. All of our fundamental values aligned and so many of our dreams. We had a rocky start and in September I found out he was talking to another girl even after he asked to be exclusive. I forgave him and we worked it out. We continued to talk about and plan a future and allied about kids and careers and even the idea of retirement in his home country. A week ago he broke up with me and could not give me a reason. He was never the best communicator and always avoided conflict, but we worked toward improving this and towards the end I really thought we were getting better. I am not sure what changed and he still can tell me he loves me, he finds me attractive, and he wants to be with me.. but yet he broke up with me? I love him so much and I want to respect his decision to work on himself but it’s hard to think about waiting without knowing he wish to date me again, and even harder to think about moving on. When I picked up my stuff yesterday he even said “I hope I can figure this out for myself before it’s too late and I lose the love of my life” which feels so selfish.. I get working on yourself but I don’t understand breaking someone’s heart in the process and acting like you can come back. This breakup feels so wrong and he really feels like “the one” even a week later. I still can’t listen to the radio or watch any shows and I get sad every time my phone lights up and his face isn’t my wallpaper. How do I move on to accept this breakup and eventually actually move on from him?