We usually use ''vous'' when you address to more than on person. We use also for the person to whom you want to show a certain respect which may include unknown, your boss, senior or elder. - Want to introduce your wife to more than one person Je vous présente ma femme - Want to introduce your wife to the CEO of your company (to show respect or to stay formal) you might use ''vous'. Je vous présente ma femme. - But with one of your friends, no need to use ''vous''. Just, je te présente ma femme.'

Actually, it significates "Je présente ma femme à vous", which is not correct. That is why it is written "Je vous présente ma femme". "vous" stands for the person whom the wife is introduced to.