I don't believe there is going to be anything that you can do for him at this point or maybe anymore. I am sorry for that, I know it's painful. But like you said, your number one priority are your kids.
How long have you been married? Regardless of what your husband is dealing with, be it bipolar or drugs, or whatever--He is being abusive, and to me, that is grounds for ending things. The only reason I say that is because of the abuse. I don't see it chaning or going away, especially because he will not be dealing with it. This is so awful I know, because I know you love him. But you cannot live like this and your children cannot go through this messy stuff. I know he's making threats that may seem empty or for attention, but you never ever know...
It doesn't matter that sometimes his mood is okay, because the rest of the time, he is not okay. I'm not telling you what to do, because I'm not a professional, but if I were in the same situation...I would not stay in the relationship that is putting me and my children at risk. I know you are protecting your children. I just don't feel at all that you can help him; and that has nothing to do with you, it has everything to do with him.
Again, I am so sorry you are having to go through all of this and having to make such hard, and painful decisions. You are being very strong, keep that strength; it will help you get through this.
Bipolar II, Anxiety/Panic Disorder
--currently not on meds for bp--