I am so sorry to hear what has happened to you and your family.
The most important thing you need to accept is that none of this is your fault - it is your oh that has the problem. And he does have a problem, which means he needs to get help immediately. I know it is very, very difficult but you must take the advice and not let him near you and the children right now. It is also essential that you phone one of the helplines to get advice and just to talk. Nothing you say will shock them and it will be in total confidence.
It is also a good idea to talk to the police - don't worry about doing this, they will be very understanding and they will give you all the options open to you. If nothing else, it will probably act as a deterrent to your oh and stop him coming near you and the kids.
I really hope you keep posting here and talking to us all.