I know this is an old post but I just wanted to say that I completely understand your situation. I was dating someone with severe chronic depression for 4 years. I had initially believed he got better, only to find out he was hiding frequent suicidal thoughts from me amongst other things that caused him to function poorly and withdraw from me. I suggested/still suggest he goes to therapy or at least gets on meds of some sort but like you said about your boyfriend, he just won't do it! He makes up excuses or just plain doesn't follow through. Our mental illnesses certainly weighed each other down. My therapist agreed. It's hard to let go of someone who you have formed such a strong bond with, especially people like us who often have a hard time finding such a close bond with anyone.