Letting go of the past. Help

Hey ladies a I have made a post a while back ago about my bf drunkenly cheating on my one time at a party. So a quick recap. So one night he went to a party got blackout wasted and he had sex with a girl from the party. He doesn’t remember the night and the girl hit him up a few days later and told him what happen. He then told me the next day he found out. We were broken up for about 5 months. He put up a fight to get me back. He said that was the worst thing he could ever do to me and he is truly sorry and that he’ll never forgive himself for it. I came to here for advice at the time and many of you guys told me to take him back. After 5 months I did.

After that whole situation he has changed in a good way. He doesn’t party anymore. Doesn’t drink. He puts his focus on me. I mean he always did but now it feels like he does more. And he puts in 10x the effort to make sure I’m happy.

He’s the bf that I always wanted. I didn’t want to get back with him until I felt a have truly let it go. But I have found myself remembering what happened lately and getting really sad as if I didn’t let go. I try not to bring it up to my bf because I want to leave it in the past but sometimes I find myself in a mood with him because of it. Lately I’ve been having dreams about the whole situation. And it feels like I’m going backwards. Not sure why. Idk if it’s this quarantine and the fact that I’m home all day and that I haven’t seen him in over a month. But idk what it is. Am I going backwards? How can I move forward? Any advice. I don’t want to break up with him he’s my best friend my other half he treats me like a queen and I was happy with him once again until these last couple weeks.