What's the problem? I'm not a Judge, but I've had about every x-wife-child issue there is to be had. I pretty much live in a court room. I have custody of my son and my x is always trying to trump up a way to get him back. I'll bet there are more than a few guys on here with some experience in x wives.
Amen Brother! I too have gone through hell. What kind of advice are you looking for? I have had enough hours inside of a courtroom to earn a degree in law. Hopefully we can help you out here.
Fly
In all seriousness try to treat it like a business decision and if you can leave the emotions out of it, it's better. I know that's sort of impossible though. Think of the children but fight for what you want.
Also, keep your nose clean. Don't give her anything to use against you.