What should I do?

So this guy and I had been seeing each other for about 6 months (never dated) we had a mutual decision to be just friends with benefits but then we fell for each other and he started saying he loves me (still not entirely sure all his feelings were real or if he just faked it). He was my first time and we grew a real connection but recently we completely stopped with any romantic talk and said we should just stay friends because he really likes me and wants a real friendship with me. Fast forward to me crying about it for weeks because I really loved him etc.. I’m over it now and completely okay with being friends. So I went to see him yesterday after a month of not seeing each other (I made sure he was social distancing and so am I) and he made me basically feel like a prostitute. As soon as I got there he started feeling me up and me still having that love for him obviously loved his touch but he wasn’t romantic or nice about it, he basically just had sex with me and asked me to go down on him twice and then watched a movie and then I left. So this is probably a dumb question but why say you just want to be friends and not text or do anything romantic or intimate but then have sex with me? Is he using me for sex? That little part of me really wants to keep the friendship because he was my first and ALSO he is sleeping with another girl during all of this (hasn’t seen her in a month though) and I’m not sure if he’s lying to me by saying they’re not in a relationship just to get sex out of me (they’ve been seeing each other for about 4 months.