When I left my exH, I sent him with almost every possession that we had, 80% of the money and no regrets. I knew that we would lose it all in legal fees if I fought him for more. I didn't care about the possessions or money, I only cared about my freedom and happiness. However, I didn't do it with children. He has a financial responsibility to them. It seems that if you could get in front of a judge, you could get child support and legal restraints on his access to the kids.
If you go that route, then there would be legal ramifications if he steps out of line. It is a tough place to be and I am very sorry you are going through this now. I haven't been in your shoes, but I have never regretted what I gave up to get away from my ex.