Why did he sleep with me and do that ugh

I (22 f) met a guy (26 M) through my coworker. The guy is my coworkers roommate. I always came over to hang out with my coworker and ended up sleeping with his roommate a couple times. He was only my 2nd body and I was like his 18th and he knew this 💀. Long story short one night it was my coworkers bday we invite other coworkers over to his place and the roommate is hanging w all of us. Fast forward a couple hours later I walk in on his roommate(the guy I was sleeping with) making out with another one of my girl coworkers and I go apeshit on them. I get into a screaming match with him we go back and forth telling each other awful things and he says things like “ I don’t like you” you’re annoying, and he was telling me that “I need to get my experience up” things like that. I come over a month later and he makes a scene that im at his place and is texting my coworker things like how dare you have her over here when she disrespected me and caused a scene and he’s doing the most like slamming doors because he’s pissed I’m at his place. I wasn’t allowed there after that but a month later he texts my coworker and says I can stop by if I need to and that he overreacted and was a dick about the situation. My question is why did he cause a scene and why does it matter to him if I “ disrespected him” if he said he doesn’t even like me and finds me annoying? And why did he sleep with me?? He knew I didn’t have a lot of bodies and was inexperienced so why did he do it if he knew he was going to end up treating me like this?