It's my ex's weekend to have the kids. We are going through a difficult patch where we aren't getting on at all in the slightest. I wouldn't give him the pleasure of asking him to swap a weekend so I won't see the kids this Sunday. He knows it's Mother's Day and he didn't offer.
I know IABU because I should have asked him but then he'd have refused and gloated
But damn I wish I'd asked and I am pissed off.