No. This is not “normal ADHD behavior.” This is behavior of someone who is struggling and not mentally well. He sounds both verbally and emotionally abusive right now. No one can really decide this for you, but from an outsiders perspective it sounds like an unhealthy place to be right now in terms of your own safety and well being, as well as that of the children. It may come to a decision point where you have to decide if you want to continue with him. Maybe he can change, but right now it sounds like a situation of concern.
If he is threatening suicide, or using it to threaten you and control your behavior, that’s a big sign that things aren’t well. Also, if he threatens suicide, there’s nothing wrong with calling 911 and asking them to check on him or take him to the hospital for evaluation. If he truly is not doing well emotionally, it may be time for more aggressive mental health care.
Take care of you. Get support where you can. And consider your options and what your bottom line limits are.