"It's not a financial or support issue" - meaning that she has enough money to support herself without working without child support or alimony from you? What, is she independently wealthy? Or have you just agreed to completely support her so long as you get 50:50 custody? Is that going to go on until the kids are 18?
Now, all other things being equal, if she is available to care for them after school and wants to, why would you object? So long as you get your full 50:50 I don't see a problem.
