I realize this is a very difficult time. There is most likely something going on that your husband can't quite explain and can't control. The most important thing you can do is be supportive. I highly suggest you contact North STAR Mobile Crisis Line at 1-866-260-8000. http://www.lifepathsystems.org/MH/Overview.aspx If any anytime he makes threats that he is going to do bodily harm to himself or others, don't hesitate to call for an involuntary commitment. I know, that sounds very extreme, but it can be the first step to getting him the help he needs.
I have experience with these issues. Making the call to involuntarily commit my father was a very difficult decision. Once he got well, he actually thanked me for it.
Try the crisis line first and see if someone can help there. They have a wealth of experience. I know it's hard now. It will get better. He needs you know more than ever.
[Originally I wrote this providing numbers for Pittsburgh because I thought you were in Pittsburgh. I found the LifePath information online. I do hope they can help.]