. . .and I would like both the W and I to be accessible to our kids. They need both of us.
You may want to go ahead and reassure her of that. Don't feel the need to tip your legal hand or otherwise "rescue" her from what she's doing, but this one's a biggie and there's no reason why you can't let her know that you have no intention of keeping her from the kids.
Starsky (who's no longer driving the "fully-moderated" Gran Torino)