I(31M) had been seeing a therapist off and on since I was about ten years old. I used to be like that, to where I felt like I had to share everything to the girl for her to truly love the real me. I realized later that that was a huge mistake! They don't need to know literally everything about the guy and some mystery could go a long way. Especially when you first start out.

This is probably due to the fact that most guys don't talk about whats bothering them (their feelings) enough, so when they do, it breaks the dam and it all floods out. When something so underused like expressing oneself is presented they dont know when "some" becomes TOO MUCH. I imagine its like a kid learning social norms, which sucks for everyone, but it is the result from the "masculinity" mindset. We as a society should gear to change that, but I digress.

It's a learning point once you get to the point of tmi, because you cant go back and the damage is done. Hopefully the guy learns where the line is (eventually) and gives little by little when needed. On the womans part, you would have to tell him where you stand on everything, and then leave if thats what has been decided. Or just leave, but I suggest explaining your side so he can learn where he went wrong. People are complicated...

Tl;dR: Men (in general) need to learn how to express emotions better. If they make you uncomfortable, (give brief reason, so they can learn... Hopefully), then leave.