Sometimes your upset is because this incident is yet one more example of a trend in your marriage. This yet one more incident where your schedule was not taken into account at all. Lousy investment practices, upsetting parenting tactics, selfishness.
Lead with the big picture and bring in the latest incident as ‘evidence’.
In other words, don’t start with the incident and then bring in the overarching problem in the same conversation.
“To me, there is a negative trend here. There are many incidences that my schedule isn’t taken into account at all. I then have to work out all kinds of alternatives and contingencies to work around major inconveniences. This latest incident is just the most recent. We must work out something that feels more reasonable to both of us.” is much better than “I can’t believe you. You took the car and I had to take 2 buses to take the baby to the doctor. You always do this. Like last week, you planned …. And the day before that you did ….”