how do i get over him

Unfortunately you offered him the path which offers you the least. A friend with benefits is often neither a friend or a partner. They're a fuck buddy. They get sex, you get sex, nobody gets much more than that. It may be a gender stereotype but it's also undeniably true that men are generally better geared up to having sex with none of the responsibility that comes with a relationship. So really he gets to have you for his needs but you don't have him for yours. Even worse, you are left with the illusion that you have him when you don't. It's pretty obvious that he won't want the situation to change now because he's got things all his own way. The cases of friends with benefits turning into relationships are, anecdotally at least, extremely thin on the ground. I don't recall hearing off any and I've heard of plenty of friends with benefits situations. Indeed, the friends with benefits agreement could be considered a death sentence for any prospective relationship.

Nevertheless, if you're not getting what you want then getting less than you want will never make you happy. On the contrary, it will make you more unhappy than having nothing at all, certainly over the long run.

truthfully, I think you gotta sort out what you really want

The fwb is always a bad move.

You were struggling with body positivity but started having sex with him anyway. What? Sounds like it’s all in your mind. Also how does casual hookup make you love yourself.

You tell him simply that you are going to start looking for a relationship. If he is not willing to be that person, then the benefits need to stop when you start seeing someone else. The risk of someone else having you may drive him to make a decision. Though it may not be the one you most want.

Ultimately he needs to either step up or step away to make room in your life for what you desire. You do not have to rush him, just communicate that you are seeking a committed partner and he can be that person or he can be a friend without benefits when you find that person. If he can't do either, I would question how good of a friend he is.