I also slipped in the idea that I had a date with me. She was definitely not happy. She argued that she should have had the right to have the kids stay with her since I went out.
I agree with how you handled this situation. Your designated time with your children is yours to do however you choose. The above statement was her way of trying to control what you did! Glad you called her hand on it.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!