As hard as it would be for you, I think that he SHOULD have them for those days. He is their father. He needs to have the responsibility. I can understand how hard it would be for you to do that, though. Could feel like you using the kids for a purpose, but I don't see it that way.
And there is no way that he could get full custody over you. I'm pretty sure you have documented everything, as far as the time that he spends with them.
Or the LACK of time he spends with them.
Me 47, WW 38 SS18, D15, D10
Good Bye Girl. No longer SAYING she's moving out. GBG moved out 8-1-08
"I have now decided to enjoy life instead of figure it out."