I too want that man I started out with. But I've come to realize that even if he stays sober, he will never be the same guy. It will be a new sober man that I will have to get to know all over again. Things will change, the relationship will change, and trust will have to be re-earned. It sucks!!
I have to leave to protect myself. If things are meant to be, then he will get sober and in time we can start "dating" again. If he can't get sober then I will just have to close this chapter, mourn my loss, and try to start over again.
PS In the bathroom at my work someone hung up a framed sign that says "One day at a time". Sometimes when I'm having a bad day seeing that helps put everything into perspective.
I hope you are able to figure out what is best for you and your kids. Good luck.