Sorry, OP. That's a seriously rough situation. For starters, though, I think you need to wait and hear back from the UC! If you got in there, would you be happy with that choice?
Assuming that the UC doesn't pan out, have you looked into options for deferral? From what I understand, it's very school-specific whether deferral is even possible - with some schools not allowing it at all, some allowing it relatively liberally, and others really requiring that you have something incredible lined up for your gap year (like finishing a degree, doing a Fulbright, etc.).
Lastly, is this partner someone you could really see yourself being with for the rest of your life? On the one hand, you mentioned that he brought up getting engaged but then it also sounds like he's willing to break up with you if you don't postpone medical school. I understand not wanting to be long distance--I've done it; it's awful. But it seems a little extreme to expect you to put your career on hold. Especially since it sounds like he might be ready to move with you after 1 year. I think it's worth asking yourself how much of a sacrifice you're willing to make to make this relationship work. Is your partner someone who's generally willing to make sacrifices? Because being married to a doctor doesn't seem easy either.
