On an address with the name as say;
Mrs M E Smith
When women is called Patricia Smith
But husband is Martin Edward Smith.
Why not Mrs P Smith
There must be a fancy term for this.
My MIL does it. It sends me up the F wall. I am a person in my own right than you very much.
On a birthday card or something personal she will still write it as
Mrs M E Smith.
I think she does it because she sees son as coming from above me, and so I'm lucky to be part of her dynastey.