They may also be able to help with the legal issues, or refer you to attorneys who can help. They will know how your state's child protection agency handles these cases and may be able to intercede or speak on your behalf. Don't feel sorry for him. He can change if he wants to, there is much help available, and he certainly knows that what he does is wrong. He just can't face the work involved in changing.
Many abusers never change, just as some alcoholics die alcoholics.
All you can do is protect yourself and your kids, and insist that he get help. Your local shelter should have support groups you can attend, also. They can be very helpful during this rough time. Leaving an abuser can be the most dangerous time for you and your children . You need to make plans for leaving, and make safety plans for emergencies which might arise out of your husband's attempts to keep you from leaving.