If it's a couple you would introduce the man first and either his wife or his girlfriend second. Example: I'd like you to meet our friends John Doe and his wife Jane. If it's a professional person such as a doctor; professor; clergyman then you would introduce them with that title and then add 'and his wife Jane.' If it's the woman that is the professional then it would still be: Mr. John Doe and his wife Dr. Jane Doe.
