I'm so sorry you are hurting. I was separated 15 years ago and thought for certain I must be the only mom going through this at my daughter's preschool. Nope, I wasn't and that is where I met my best friend to this day.
I hope you can find the strength to work through this for the good of you and your kids. You mentioned that he is "working on it" and I immediately thought he was with other women. Looked at your post from a year ago and he cheated for almost four years.
I don't see how it would be better for him to come back (when he is hopefully done being a pig). Would an "intact" family be nice? Sure but you need to look at the example being set for your kids. Good luck!!