My wife and I have a pretty good relationship. She's my best friend and we can joke and be silly, more so than I can with any of my guy friends. Saying that, don't take offense to some of the things I call my wife, as I'll try my best to explain. Also she knows every nickname I have for her.
I might refer to her as "the" wife sometimes, because she IS the only wife, to me. I also call her my goddess and the lady bug.
I ALSO call her my bottom *****, (yes from south park, lol.) She takes care of me and she gets **** done. That girl would stand with me in a fight, fist or gun, and I would feel protected.
I cant say what other men may infer when they say "the" wife, but for me, it is one of my many strange terms of endearment. It just mean's that she's the only woman in the world.