I agree with G - unless your W is a whack job or addict, it's better for kids to be with a loving parent after school. And it might actually facilitate things like schoolwork getting done etc. If she can make a living seeing clients from 9-2 and caring for the kids after school, that's great - JUST so long as she doesn't then try to drag out the process when you come to pick them up. If she picks them up at 2:30 and you pick them up at 6:00 and it's clear to everybody, that's great.
And I agree with the poster above - she's giving up retirement and other benefits and making a lesser income in order to accommodate being there for her kids - those of us on the mommy track give up a LOT financially.