Advice please

I need advice for my own health about 4 months ago I was talking to another guy other than the man I was engaged too and ended up having sex with him and 3 different times excluding the time I was drunk and when I was drunk I didn't even know I did it and now the man I'm engaged to has been really mean with me saying least his ex never cheated on him and saying hurtful things telling me to leave are house and when I'm hurt don't care anymore and before I even did anything with the other guy I told him I didn't want to be with him anymore so did I really cheat on him? Do I deserve to still be treated like this? What exactly should I do or say to make him love me again or is there nothing I can do !