Janniebug,
I too suffer from borderline personality disorder and was in the hospital for a few weeks last year. The guy I was dating at the time actually called me at the hospital and broke up with me then. Pretty bad huh?
I think that your boyfriend sounds confused but he also sounds very ignorant and kinda oblivous. Frankly any guy that would say that to someone he is suppose to care about is kinda a jerk.
I understand how you feel hurt about him "wanting to keep it a secret." Your BPD is a part of who you are. You did not ask for it to happen to you nor did you want it I'm sure. It is totally unfair and mean of him to treat this like your fault and you should hide it from everyone.
I think anyone suffering from "disorders" (i hate that word) should really be with someone who is understanding and supportive. You do not deserve to be with someone who cannot accept who you are and blames you for something you have no control over.

Stay strong,
Jessica

You are in this snowglobe. It is encovered in glass and secure. But one day someone comes and shakes the globe and the pieces go flying everywhere. Now they will eventually settle but they won't be the way they were before and they can never be that way again.