Invitations

We will be inviting my FSIL's boyfriend to the wedding. My question is whether we have to send him a separate invitation or can I just put his name on the invitation I'm giving to my FSIL? What is the proper etiquette? They've been dating for some time now so he's not just a casual date.

Invitations

Hard core etiquette says that you only put both names on the invite if the couple is living together and should never use 'and guest.' The proper way would be to send him a separate invitation. As an alterntive, the etiquette books say that you can enclose a personal note saying 'please bring so-and-so as your escort' We took the easy way out though, and in a few cases did include both names on the invite, even though they were not living together, since it was a long term relationship. We also used 'and Guest' in a few cases where we didn`t know if there was a significant other, but knew the person might be more comfortable not coming alone. I think the only real danger here is if someone is well known within the family circle, but not acknowledged by name. They might be insulted to be refered to only as 'and Guest.'