Caigy, So sorry this is happening to you. It is appalling and frightening.
Although my STBX has not yet become physically violent, I suspect, by his rages, that it won't be long.
I'm totally with you in wondering "How does this happen? He's so cruel añd mean to the ones he would have died for. I don't get at all"
I think the massive turn-around in character is the most devastating part of all of this. It makes it all feel so unreal, and that is very hard to deal with.