Obligation??!! Ugh! I would get out. That's no way to be thought about. Even if he flip flops with it.
I see other issues going on around this (the relationship stuff). I can't relate it to my experience with bipolar at all. I should clarify too, since it had come up, that I'm not suggesting he has it, merely discussing things I can relate to. Like others have pointed out, it could be all kinds of things. Which may or may not include bipolar.
Whatever is going on, I hate to see you treated like this.