I will look into a neuropsychologist referral from peds. Thank you for your insight and advice.
He may be suffering from PTSD. He had a troubling childhood to say the least, as did I. However, we've been together for almost 13 years and I've begged for this behavior to stop and for him to get therapy (and he did for a couple of months half-heartedly and only because I gave an ultimatum), but it's come to a point that I can't take it anymore. It was different when it was just he and I, but now that we have our son, there's no excuse anymore. I don't want my son to be the way I have been, so I've gone through extensive therapy to change it. However, I don't want my son to be like him either. I'm trying to be sympathetic and view my husband's situation with empathy, but I just don't see how someone can behave that way (you have no idea the things that happen in our home) and him not want to change his behaviors somehow. He hasn't seen the fear in my son's eyes when he has an explosion because he's too busy exploding.