Prom Help!!

My ex boyfriend and I were together for 2 years. I loved him so much and genuinely thought it would last. A couple months ago I found out he asked another girl for nudes and then called another girl hot. We broke up because of this and I met another guy who is the complete opposite of him. He does treat me good even though sometimes he has his moments where he doesn’t show his emotions. Me and this other guy have been talking for about 2 months but I still keep in touch with my ex. I don’t know if I should go to prom with my ex because some feelings are still there or if I should go with the new guy because he does care about me and will be happy with any decision I make. I know I would have a good time with either or. I just don’t know what to do.