Guy's Behavior

Why is he SO MEAN?

Ok so there's this guy, isn't there always?, and I thought he liked me. Why? He flirted with me, would talk to me and single me out often etc. Anyway then he started giving me mixed messages, being nice then the opposite. Now I have found out he is talking to this other girl. That said he never messaged me directly like this girl, they talk all the time. Anyway , it's clear now he doesn't like me like that. But he still tries to treat me really well, then horribly and I don't know why. Plus he almost seems jealous if I talk about other guys. I don't get it. I don't want to date him at all but I have feelings for him which I am FIGHTING. Anyway I try so hard to be kind to him but he just isn't kind and I have a problem where I always want to help people who are mean. Which is a weakness really.
But yeah this isn't really about that it's just why is he so on-off with me, even for a friendship really? I don't get it, someone HELP me thanks :) please no stupid answers. (for clarification we are 16 years old so it's not like we are adult or whatever)
Why is he SO MEAN?
Post Opinion