I would say get over it. You told him you would give it for free with zero expectations and he’s taking you at your word.
This is the problem with friends with benefits in my opinion.
It may work for some couples but when you are an adolescent emotional and hormonal fireball and just figuring out who you are it is hard enough without this kind of complicated nuanced relationship thrown in.
I’m not saying this as some sort of adult parental figure. I’m giving you advice from my hard earned experience.
I did this a lot in my adolescence and it took me decades to recover.
You are wasting your time wondering and pondering what he does, did, or continues to think about you. Without directly asking you cannot know and all the mental gymnastics in the world won’t change that. I agree with @Judi
We were 70’s girls, with all the free love stuff that was so popular during that era, and she is right. No matter how “open” you think you might be, the reality is as @Judi points out.
You are biologically programmed right now for the “meet, mate, procreate” phase of our organisms drive and a FWB’s rarely works out, someone always gets hurt or ends wanting :more” than the original agreement specified.
In my dreams he’s very sweet when it’s just me & him, but he’s a jerk in front of his friends
You didn’t need to write 10,000 words to figure out the above fact. He was using you for what he hoped would be no strings attached sex. That’s all. You were/are trying to justify that friends with benefits is a good thing. It’s not, because it leads to this type of sad, painful situation.
Let it go, focus on your studies, then in the future, when you are more mature and have figured out what is truly important in your life, maybe you can meet someone who will care for you and respect you and treat you like you are the valuable person that you are.
Don’t ever put up with someone who treats you poorly like this guy clearly did.
@Coloma, growing up in that era between birth control and AIDS was interesting wasn’t it? If I had been born 10 years earlier or 10 years later I probably would have made completely different decisions about my sexuality during my adolescence.