Prnce William referred to Kate as 'The missis' in an interview for Match of the Day. It seems to have gone down badly judging by the Daily Telegraph OP.
I'm sorry ludwig but that's utterly offensive to people who aren't married. You should always use "the person I venture to refer to as my close acquaintance in daily life".
Well at least it's not as problematic as a PG Wodehouse appreciation society in the US discovered when they wanted to name their publication "What ho!"
Apparently, ho has a different meaning there ............. ;o)