You might try this as a way forward. It's based on a method of praying through our lives and trying to see what God's will is.
First, tell him you need three weeks to think about it, and ask him not to contact you in that time.
For a week try living as if you had decided to give it another go. DON"T ACTUALLY DO IT! See how it feels to think about getting back together again. Does it make you feel exhausted, hopeless, depressed ... or do you feel happy and energised?
Then for the next week try living as if you had decided not to give it another go. STILL DON'T DO ANYTHING! See how it feels to have decided your marriage is finally over. Again, does it make you feel exhausted, hopeless, depressed ... or do you feel happy and energised?
At the end of the two weeks think back, over the last two weeks. When did you feel energy and hope for the future? When did you feel a lack of energy and hope? When we are in tune with God's will we often feel energised and hopeful - when we are becoming the people he wants us to be.
I think you may well find that, as peachpudding says, God's will for you is not for you to live with someone who hurts you and your children. And that God isn't asking you to try and change him or to give him another chance. How he changes is between him and God, but your responsibility is to build a life for yourself and your children.
Give yourself time - don't let him pressure you into an immediate decision. And remember that you have done a brave and difficult thing in leaving him, and that God holds you in his hands as you make your new life.