I am planning on using belly bands for my invites and no inner envelopes. Anyone that has done this, how did you let your guests know they can bring a plus one?
Assuming that you have an outer envelope and then the invite inside wrapped in the band, I would just put "Mr. Joe Blow and guest" on the outer and only envelope. Just checking, but I'm hoping that anyone in a relationship has their SO invited and then it would be by name i.e. "Mr. Joe Blow and Ms. Jane Doe".
@CMGragain is the best person for advice on invitations and addressing.