hopping, I'm confused about what Missy said that was untrue/disagreeable. Maybe you misread?

"Dad would probably have a hard time finding an attorney to take a custody modification case in this situation."

Uhm, so long as father has money and desire, this isn't accurate.

As for original poster, I suspect that while you may have sole physical custody, you don't have sole legal custody (as in, the father has no rights to decision-making related to kids' lives or anything other than visitation).

"Once custody is initially determined it is very very difficult to change."

As a blanket statement, this isn't accurate.

"Just because one parent's situation changed (which happens all the time) doesn't mean they get custody. "

That's essentially what Missy pointed out though.