Past behavior and lack of change on his part would indicate that there isn't much hope of any change, tazzer.  If he has NPD, the prospects for any kind of recovery are very dim, mostly due to the fact that narcissists don't really think there is anything wrong with them.  They may go to counseling to appease, but they usually think they are smarter than the counselors.  Even in counseling, it takes many years to even make a dent and even then, the best that might be hoped for is that they learn to 'act as if' they care or have empathy and then it is only because it's in their best interest to do so.

NPD is essentially a set of defense mechanisms that the N has adapted and they work for him.  He holds on to his false self for dear life because that's really all there is.  There isn't much motivation to change in that equation. 

As to your children, they will likely be fine with one 'good enough' parent and that person would be you.  He will never be that person whether he is with you or apart from you if he's an N.  I think the best lessons we teach our kids come from showing them the healthy thing to do.  Your happiness and your well-being are pretty important in what you model for your kids.  That speaks much louder to them than hanging on to something that isn't good for anyone. 

Hugs,
Lynn