I'm not about to try it right now (don't want to mess up my contacts) but I'm pretty sure you can just tell Siri that "suchandsuch is my wife" and she'll update the relevant Contact cards for you.
"so-and-so is my wife" => it will update that contact's info (and yours). Then later you can say "text my wife I'm on my way home" and it will.
"call me Mister Smith" => it will update your contact's nickname and use that to address you
"Take me home" (or to work/etc.) => it will bring up directions in apple maps to the "home" address on your contact
All devices need a universal undo so you can change something and easily undo if you get it wrong or you just preferred the old setting.
For security you could prompt after a while to make the new settings permanent and delete the snapshot.