Eh… ESH

While everyone is responsible for their behavior alone, you are the one who caused the first domino to fall. I think people would have understood if you got yourself pizza, but you 1.) put it on your husband to buy it for you and 2.) told him(?) to buy enough for everyone, so either they were going to eat the pizza or it was going to go to waste.

At the end of the day, it is just a dinner and there will hopefully be more opportunities to dine out together as a family.

People often make predictions for the future based on the past. Is this the first time something like this has happened? Or is this enough of a pattern to warrant your sister's response?