Is this piecing?

[Freckle6]

Hmmmm. A sitter he doesn't object to might help, but the thing that jumped out to me is that you're basically asking him for permission to do whatever because he knows you need him to watch S and he's taking that as an opportunity to throw his weight around and give you a hard time about it.

What if you were to approach it as you have a commitment for the time in question. Those plans are firm. You're not asking him to watch S so you can do whatever it is you are doing, but rather letting him know you have plans and giving him the heads up on if he would like to switch (or maybe even add time to--like in this case instead of switching mon & tues. to add mon with the planned tues visit) days and have S while you're out or if that doesn't work for him, then you will have gladly arrange for Sally the wonder babysitter watch S. Cue robot wife smile. LOL

I know I've hard about some D agreements that have a clause of first right of refusal in regards to the kids and "babysitting". That the parent who doesn't have physical custody of the kids for this time is supposed to let the other parent know of times they need child care and that parent has the option of having the kids rather than needing to use a babysitter. The one parent isn't necessary asking permission from the other to do whatever their plans are, but is offering up this "free" block of time with the kids if they'd like to (or can) take advantage of it. And if he starts going off the deep end, I wouldn't keep repeating yourself, just take it as a "no" and tell him that it's ok, and you'll call Sally ASAP and take care of it. And then act as if the conversation is done.

And I'm sure you're right about timing. Would this maybe be something to bring up in MC? That you don't want to tie him to your schedule and understand it's not fair, just as it's not fair for him to do the same, so how should we handle this when one of us needs, for whatever reason, to deviate from the status quo schedule?