Jic,
Re this comment:-
"He is a good dad, and the kids adore him"
Why did you write the above exactly?.
Women in abusive relationships often write along the above lines when they themselves have nothing, yes nothing, positive to say about your man.
I know nothing of your past except about reading of abuse you alluded too. Presumably your mother may have thought the same; look where those types of thoughts have got you now. You were preconditioned to accept abuse and you're now within an abusive marriage. The two are connected.
Abuse too goes in a cycle and am sure he does the nice/nasty part but its a continuous one. (What do you yourself know about this man's childhood; this is often learnt behaviour. You learnt how to be abused, he learnt how to abuse others.
Your children cover their ears to try not to hear it, they too clearly see how their dad treats their mother. It is extremely damaging for them as well even if they are not seeing all this directly. Their childhood is full of fear and loathing (perhaps towards you both) as yours likely was as well.
You cannot remain within this abusive relationship; he will destroy you all ultimately along with your children as well who could go onto repeat abusive type patterns within their own relationships. This is no legacy to leave them, it truly is not. One generation i.e you remains profoundly affected, it is your responsibility not to let the second i.e your children go down that path.
He is also quite happy to drag you all down with him. Abuse is about power and control.