Might I suggest a little experiment.

Go and buy some really nice gifts for "The Wife" and have them wrapped so they look very enticing with ribbons etc. and then address them with "The Wife" ( or other term, - Wench works well too)
Then sit them somewhere like the kitchen table.

When she walks in and says "Oh are they for me?" you can say "I dont know are they addressed to you?"

After they have sat for 3 days and she finally gives in and opens them, she has by default accepted the addressed name and cant complain at ever being called that again.

A bit of fun but it does work <img src="/images/graemlins/smile.gif" alt="" />