Simple - "Please don't make plans for the children during my scheduled time. I know you mean well, but often these events conflict with other plans I've already committed us to. I appreciate you wanting to keep things as calm as possible for the kids, blah di blah blah validation"

hope that helps

M 20+ T25+
S ~15.5 (BD)
BD 4/6/15
D 12/23/16

"Someone I loved once gave me
A box full of darkness.
It took me years to understand,
That this too, was a gift."
~ Mary Oliver