If you have to put your girls in a regular daycare one day a week, that is still way better than most 2-career couples, let alone single parents.
This needs not to be your W's problem. Tell her so. You agree to her parenting schedule (for the next year) and you will figure out child care as needed during your parenting time.
Save up your vacation time. This is Plan D when all else fails. A=main sitter; B= alternative sitters; C= work from home; D = vacation. But again, this is not W's problem--the only question she should be asking is, "Is this plan acceptable?"
