Let go or keep trying
Found out my boyfriend of 4 years was unfaithful for 3 out of those years. He admitted to sleeping with one person and the rest was online messaging with others. After this he has opened up a lot and told me things he would have never admitted to before but now that I see all of this effort. I don't know if it's too late. We have been on this back and forth for about 6 months now. It has been exhausting, but not sure if it's worth it anymore.
I would suggest you think about it, and although it hurts a lot is not worth wasting any more time with someone that clearly cannot be loyal.
I know you must be so hurt and upset, and so angry but remember, we all deserve a partner that can treat us right and be faithful to us.
My advice is that you let go, however, i am aware that is easier said than done.
Wishing you the best.