Almost a definition of bipolar? I do not think it unrealistic to think he will get stabilized and learn a bit more about himself and his illness as he lives with his parents and maybe you two will get back together. If he is sometimes hinting that he doesn't know when though, it might be better for your own mental health if you find a smaller place you can afford so you can save some, etc. and not exactly "get on" with your life but put yourself in waiting mode for as long as you decide is reasonable for you and then you all can get together or not. I don't know that he was telling you things were ending so much as perhaps sharing his feeling that his life IS uncertain at the moment and he doesn't want to be an inconvenience to you.

It can feel like pressure if another person is just hanging around waiting, keeping everything the same (it will not go back the way it was, both of you will have to move forward together, if you do, in light of this illness, it's not like a regular illness where he gets "better" and you move along as if nothing happened, this illness is there for life). But with mail and his stuff at the place, etc., he might have in the back of his head, "I must hurry up, she's waiting!" and that is not very relaxing and conducive to concentrating on one's self and getting well?