I’m choosing to take everything you’ve described him doing and saying at face value.

As such, this would indicate he has some deep-seated issues with self-confidence, or intimacy, or both - the types of issues I’ve listed are purely speculative, I have no concrete idea what his situation is. Either way, the relevant part is that he seems to have some work to do with himself.

Have you two discussed therapy at all? Based on your description, couple’s therapy may be a tough sell, but if he isn’t already, he should consider going to therapy by himself, for his own sake. It sounds like he’s having a tough time dealing with the context of a relationship, which translates into a rollercoaster ride on your end, especially if he goes back and forth between wanting to stay (for whatever reason, although “because you’re there” is… well, it is how it is) and wanting to leave (again, for whatever reason).

This push-pull will wear you down, especially if you genuinely care about him. I would recommend starting to consider the options you have at your disposal now, because you do still have full control over your side of the relationship. You can try to discuss things with him and frame everything away from a potential break-up (i.e. ‘neutrally’ broaching the subject of his wellbeing, of his state of mind, etc.), but at the end of the day, we can’t help other people by force.

I’m sorry you’re going through this, these types of situations are beyond exhausting…