If I am addressing an invitation to a married couple who have the same last name do I have to put:
Mr. and Mrs. (husbands first and last name)
or can I put:
Mr. and Mrs. (husbands last name)
The websites I've look at say the first one is proper but I feel kind of weird putting the husbands first name. Is it a must or is it acceptable to put just the husbands last name?