They are probably fearful and intimidated by him. Even if they've never seen him in action, they pick up on the subtle atmosphere. Kids are aware of much more than we think. You say you are living in hope. He could, of course, but the chances are very good that he won't, at least not much.
Some abusers do stop the physical stuff, if they get in trouble for it.
But, sometimes, that's not enough, either. They might stop for awhile, but then start it up again. It's not easy to change this type of abuse. Your partner is very violent and dangerous. He sounds like the type who might end up killing his victim.