"They'll never learn if I don't correct them"

Some of the arguing has a teaching motive. If you let the wrong route stand, they'll take it again. If you don't correct the recipe, the cake will fail again. Correction is how people learn, and you're doing them a service.

Consider what people learn from being defeated at dinner. In my observation, they learn that disagreeing with you about a route ends in a demonstration that they were wrong, with evidence, in front of the children. They don't learn the route. They learn to stop offering routes. The next time there's a choice of ways to go, they'll say "you decide", and you'll have won the road and lost the passenger.

Nickola Overall and James McNulty, in a 2017 review of what kind of communication during conflict helps couples, drew a distinction that's useful here. Direct opposition, saying plainly that something's wrong and needs to change, was beneficial when the problem was serious and the partner was able to change it, and harmful when the partner wasn't secure enough to respond. Cooperative communication, affection and validation, was harmful when a serious problem needed changing, because it left it unchanged, but was beneficial when the problem was minor, couldn't be changed, or involved a partner whose defensiveness got in the way. An earlier book in this series uses this review for the case where something serious does need raising. I'm using it here for the other half. The plumber's day is minor. The route to the in-laws is minor. What was said at Christmas can't be changed. For those, direct opposition isn't teaching. It's the harmful case, and the review says so.

There's a real version of correction, and it looks nothing like the argument. If your partner really does keep taking a slower route and it really does matter, the correction is "the motorway's usually quicker at this time, do you want to try it next week?", said once, in the car, not as a verdict, and then dropped whether they take it or not. That's a correction someone can take. A win isn't a correction. It's a defeat with information attached, and people don't keep the information from their defeats. They keep the defeat.