So is your W still having the kids, she just needs you to pick them up? or?...and maybe watch them until she can pick them up from you?
She could just need to stay back at work???
I'm not too sure what to suggest until I know the answers to the above...but I guess what I could suggest you think about is on the nights your W has kids, do some GAL activity...so that you are busy. Not of course b/c you dont want to be with your kids, but it eliminates your W from taking advantage of you in that way.
One thing a dear friend always says to me is that people will only treat you how you let them treat you.
Hope this helps...
Sailors Girl LIVE,LOVE & LAUGH! & SMILE LIKE YOU KNOW SOMETHING NO ONE ELSE DOES! NO REGRETS!