How do I know if it’s just sex or if he’s actually into me?

So on Halloween I met this boy and he flirted with me a lot when I first got to the house where the party was. After that I lost him and went with my friends, I saw him with some girl dancing and I walked up to him pulled him to the side and made out with him. He was actually kind of an asshole when I pulled him aside but we ended up exchanging snaps but I didn’t wanna talk to him after that night.

Point is he would hit me up after that and he hadn’t remembered we made out but he vaguely remembered a talking. He would snap me for a month and we’d make plans to hang but they never happened and then one night I finally went over to his place and we had sex. We haven’t had sex after that because I was on my period but he would still invite me to his place. I’ve sucked his dick every time except like once out of all the times I’ve been there. I’ve asked him to hang out like to study together but he’s always “busy.” Winter break started and he snaps me every day for streaks and sometimes we talk a bit but that’s really it. And he told me he’s not talking or fucking anyone else but he could also be lying. I don’t know if this is just a JUST SEX situation or not...