I think that you have every right to be nervous, and worried about you and the children......
I would also be worried about the lying. Ok, so he is unstable, I understand this, but to lie about his whereabouts????? Doesn't sound good. He could have just told you how he felt, and what he was planning on doing. The lying just doesn't add up here....It the mystery involved, the planning, the lying.....All too mysterious.....
The scissor incident, that is just plain scary. He is having blackouts, and not knowing what he is doing. No telling what he is capable of if he has another one.
I know that you probably don't want to hear this, and probably don't have a clue as to what or how to do this, but, personally, I think he needs to be hospitalized, where they can get him under control again. Through therapy, meds or whatever else it would take at this point. He is out of control and he can't do this on his own. At this point he needs professional help....