This happens with us more often than not because we both love to taste everything. Sometimes we end up ordering the same thing and I almost have a pang of--well, not guilt, but regret at the lost opportunity. And sometimes I deliberately order the same thing as Mr. Fox just to remind myself that it's just a meal and not, say, an important food research opportunity. (this is almost subconscious--I really don't agonize over it)

Conversely, I have been in situations where I got the distinct impression that it was not cool to order a different meal from everyone else. It wasn't even a question of price, if someone else was paying, but, hmm, conformity as a way of validating the other diner(s). Felt very strange.

If your spouse is agonizing between two choices maybe s/he should be the one to order the entree that you don't like!