I'd try to test it for you, but here in Texas right now Siri is being petulant. "I can't take any requests right now." Been that way for me for more than a couple days.
But, from what the instructions say on the Siri on/off switch, just turning Siri off and letting it sit off like that for a minute should clear, or at least disassociate from your iCloud account, the things it's learned about you. So, if anything, I'd trying turning Siri off, wait a couple minutes, then turn it back on. Try again. See if the wife relationship sticks. Otherwise, file for divorce, find a new girl, start all over again. ;-)
Seriously, though, from my experience most if not all my Siri problems I've thought were local to my phone were actually server-side problems, and resolved in their own good time. The little fixes infrequently worked, and when they did, I think only by coincidence. Perhaps, as part of maintaining or upgrading Siri, something isn't working for relationship flags, or those flags keep getting cleared. I'd say a complete reset and restore is a little extreme right now, unless you have the spare time and don't mind the hassle.