Sapphire2012,
I had to review a few of your posts to remind myself of your romantic relationship. Now, I remember.
Your bf is fighting an illness that brings up more extreme emotions and behavior. Finding the right medication, doctor/s, and pattern in life can take some time. I hate to sound negative, because I do remember how afraid you are of losing your bf, and I really can relate to that fear. But, I honestly think that getting out of this relationship would be best for you and your bf.
Maintaining a healthy relationship takes time, effort, and desire. You can't do it by yourself, and neither can he. Your bf needs to focus on getting himself to a healthy state of mind. You need to focus on maintaining your healthy state of mind, by not holding yourself down anymore.
Being alone is a very scary concept, I understand.

But it doesn't take too long to get used to having a little more space. Making some more unchallenged ideas. Deciding what to do and when to do it actually feels good the more that you do it. Things DO become easier....really. Picking up a new hobby or two really help a lot too!!
Very best wishes to you...