IIN he isn't ready for a relationship but doesn't want me to leave?

I can relate to your boyfriend.

I think it is very possible to not be ready to have a relationship. I am at a point in my life where having a boyfriend is stupid, and I am not ready for a "relationship" with labels and ties, but am fine with something looser, like having a person in my life who I truly care about and who I am committed to...just without the label. It is something more primitive than the typical relationship. Of course your boyfriend doesn't want you to leave; he cares about you. If he is anything like me about this, it's a hard feeling to accurately explain to other people.

It's hard to explain. I was actually in a relationship when my mindset shifted to where I do not want a relationship, just a partner, and I couldn't even explain it to him well then.

Take everything you consider a relationship to be, zoom it out, fuzz the lines, don't think so hard, and loosen it up. That's what having my (and it sounds like your boyfriend) mindset feels like. Sorry if that all seems like a mess.