I need advice

I finally had sex with this guy I’ve had a crush on for years now. We live in the same apartment complex...BUT since then we haven’t talked and after it was weird and awkward. I want to confront him because I thought that at first it was AMAZING, but then it all kinda went downhill our bodies were saying otherwise. Also, I know he’s talking to another girl and there’s a lot of ladies in his dm’s/ phone literally everywhere. Did we do it because I’m convenient and I was there? Or because he’s actually into me like his friends say? How do I start the conversation? H E L P