You have lost sight of yourself.
You have lost sight of your own importance, the importance of your own life, your importance to your children.
All because of this man and his cruelty.
Stop wringing your hands. The only choice to make is a life where nobody but you holds the key to your happiness.
Stop going back over all the details looking for justification for both of the options you face.
The problem in your relationship isn't 'did he do that and was it really that bad'?
The problem in the relationship is power, power that he has wielded for years for the purposes of destroying you.
To put it very simply, the problem is that you have absolutely no power in this relationship and as long as you stay he will have it all, you will have none, and he will destroy you.
You cannot let him destroy you.
This is not the reason you were put on Earth!!!
You have no concept at all of 'future'.
He has robbed you of that.
You need to work very hard to reclaim trust that tomorrow, next week, next month, next year will see you with an abundant life, and encounters and experiences that affirm your worth.
If he is changed then he will still be a new and improved version of himself ten years down the road and you can decide then if you want him back. Time is the true test of change.
You have panicked at the thought that he would find someone else. Well maybe you will find someone else? Or maybe you will find blissful peace as a single woman?
Can you trust that you might change over the course of a year, five years, ten years?
Can you accept the reality of time and a wide and free universe in which you live and move, and do you understand that you have the capacity to grow and to be renewed by new experiences?