We invited my fiance's uncle and aunt to our ceremony and reception. We got the RSVP card back with his Aunt's name and one of her co-workers who neither one of us has ever met. We don't feel it is right for her to invite someone other than her husband since the invitation was addressed to his uncle and aunt.
Do we have a right to say this co-worker isn't invited and if so, what is the proper etiquette? We wouldn't feel this way if the invitation had said "and guest".
Help and advice?
Thank you.