If he justs wants to save money, then there are better ways of that! If he wants to be closer to his children, then he needs to move closer to them and make a happy medium between his job and his family. If he wants to be with you, he will.
You obviously love this guy, and I completely understand how this affects the way you think about him I HAVE BEEN THERE. But maybe you should look at the situation through someone else's eyes.
If you want to be friends with him w/o any other gratification romantically then try and see what happens. But if you are looking to be close with him in order to get back together, then just leave him alone! You DON'T want to be drug along behind him. Right now, you're obviously not sure of how to handle the situation so sit down and seriously think about how YOU will be benefited by keeping your friendship with him and if it would really hurt you to find out that there IS something going on with him and the ex. I'm not saying that something is happening with them, but what if there was? Would that bother you, if so then you should let go of him.
I hope someone on here can help you with your problem even if I haven't!