He's changed for the worse but I still like him?

Yikes. Sounds like he might be a little possessive, which is not good! If you respect his personal space and the fact that he needs time to live out his life, then he should do the same. If he can't understand that, he's not worth your time. If he told you it was over, that's pretty final, and maybe it should be. Tell him how you feel, and if he keeps flip-flopping, drop him move on.