Post # 1
One of my fiance’s cousins has been dating a guy for seven years, and they live together (I don’t know his last name.) My question is how do i address their invitation, as per etiquette?
Grace H & Z
Z and Grace H
Z (last name) and Grace H
Grace and Z (last name)
Post # 3
Ms. Grace H and Mr. Z (last name)
(Find out his last name, put her name first because she is the person you know most)
Post # 4
Also keep in mind that if a couple is not married their names are supposed to appear on separate lines.
Post # 5
I agree with the previous posters that you should contact her and find out his last name. Otherwise you could address the outer envelope to the cousin, and the inner evelope/RSVP/whatever as “[cousin] and guest”.
Post # 6
We did the person we know most first (unless we know them equally, the it was alpha order). “Ms. Grace H and Mr. Z LastName.” On the inner envelope we did “Grace & Z.”