sleeper, Your wife acted like a very spoiled little brat about the child care. It was short notice and you know what? She's going to have to learn just what giving a notice is all about if and when the divorce takes place. You've been a very good person throughout all of this and yet, she's still spewing when she doesn't get her way. I think she was hoping to spoil your day so that if you had plans, you would have had to change them to accommodate her needs.
Sleeper, she'll get over it. Do what you have to do to set up some firm boundaries w/her. She's taking advantage of the situation and you certainly wouldn't just "drop" an announcement on you about the children. Time for her to think about getting some back up child care when you aren't available.
Keep your distance when she's ranting and raving and let her fire fizzle out. You don't need to be treated that way. She needs to learn to respect you and that's not going to happen if you are giving in to her temper tantrums all of the time.
Good luck!
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.