I'm sorry, but you are not seeing straight. This relationship IS UNHEALTHY. Whatever is going on with him, whether it's his biploar or multiple personalities, it is NOT STABLE. You cannot try to control him yourself by refusing to break up with him because you are afraid of what the other personality may do. This is seriously broken and faulty thinking.

Please do get some professional help. I think it will help you. I don't mean to come across as mean, so please don't take it that way. But I really think you need professional help.