We are paying for most of our wedding ourselves, so we were careful when putting together our guest list. I had a friend of mine RSVP for 2 (he is not engaged or married; and furthermore I have no idea if he's dating someone exclusively) but we clearly did not give him a plus one on his invitation. The outer envelope was addressed just to him and the RSVP card only had a space for one name.
How do I tell him that we didn't include a plus one for him on our list?
Thanks!