Of course every one of us, if forced with the choice between keeping our wife or keeping our job, would choose the wife.

But that's not the situation here. It's simply a matter of honoring commitments, even when it's inconvenient. It would be different if she had a better reason for not wanting to go. For example, if a family member had recently died and she just needed to be with her husband that night, that would be totally understandable. But the fact that the OP has to go looking for a legitimate excuse to bail on the evening is evidence enough that they don't have a good reason to bail.

This reminds me of the counsel from President Hinckley to put family first, then work responsibilities, then church responsibilities. Was he saying that in every possible instance you bail on church commitments if there is even the slightest need for you to be with your family? Of course not. He was saying that in the big picture, our priorities should be in that order, even though obviously there will be instances where we need to, for a time, allow the family to make sacrifices for the sake of one's church responsibilities. Same idea here.