2020 mess up(long story)

Man oh man guys I had sex with this dude. And I feel so badddd about it. It wasn’t planned or anything. I was over a friend house for New Year celebration but because of  circumstances I was not able to gts there and he was texting me and I told him how I wasn’t able to sleep there. So he’s going back and forth with me for a good 10 minutes telling me to come to his house and I kept giving him reasons that I couldn’t but I eventually gave in because my other friend (S) told me if I don’t feel comfortable then I should leave since I’m given the chance. Sooo I went to his house because it was like 5 am and I couldn’t get the bus home at the time and he offered to get me a ride home in the am. Sooo I went over there and you know we laid up the usual and eventually ya know we DO IT and it was literally the best I ever had but what slipped my mind completely HE HAS A GIRLLLL and ever since he’s been posting her DAILY and I feel a little jealous no lie but I’d never admit it to him or anyone else that knows him. But that shit really shook me up and I told my very close friends that I plan to hold out from sex till the end of the year. Or atleast till June/July and also I feel like he’s been ignoring me but I’m not really sure cause he responded to my snap today soooooo any advice?????