I guarentee he will leave again. Unless "I do the changing according to him"
What does this mean? Are there things that he says you have to change to "please" him, or are there things that he's right about needing changing? Are there things that you WANT to change, for your own sake, or maybe the sake of your kid(s) that would also happen to make your marriage work better?
This is a VERY touchy subject because there is either something terribly wrong with the marriage, you or him for this to be a constant in your relationship. This kind of thing, IMHO, falls outside the "norm" (if ANY of our sitches can be called such) of the sitches around here, much like serial cheating does.