Back when I was a church administrator, every Christmas we (the church) would receive a card from a larger church signed, 'from the pastors and their wives.'
Quite apart from the implied sex discrimination it's offensive and I think it's a peculiarly religious thing. You don't get cards from the doctor and his wife or the accountant and his wife. You'd like to hope their wives wouldn't stand for it. I mean, what woman wants to be or is happy to be an appendage?
I assume it's to do with man and woman in marriage becoming one in the eyes of God. But if that is the case then surely the woman must have the same authority and power as the man. Which, of course, she doesn't. She is just the wife. Useful no doubt for making tea.