I can't think why I personally would want to introduce someone as, "my wife", and only that. In my mind, it seems a bit possessive, and disrespectful. I don't feel that I own anyone.
As it happens, I'm not married, but I wouldn't introduce someone as just, "This is my partner" either. Regardless of the relationship label, wife, partner, or friend, I'd always prioritise mentioning their name first. I've always held the belief that names exist for a reason; they carry significance beyond just a title.