My fiancé and I have sent out save the date cards at this point but not actual invitations, which will be addressed to only those invited. But one of my fiancé's friends has already sent an RSVP - with a plus one. Our venue only holds 200 people and we're already pushing the limit, so my fiancé and I agreed there would be no plus ones. But now he wants to make an exception and let his friend bring a date. I'm against it - if we make an exception for one person, then I'd feel bad telling my friends they can't bring a date.
On the one hand, it is his girlfriend. They haven't been together that long and I'm not sure how serious they are, but neither my fiancé nor I have ever met her. Still, she is his girlfriend. On the other hand, we don't know this girl and I had to cut out a lot of my friends just to keep the guest list at 200. And my fiancé's friend is close friends with a good 50% of the invited guest list, so it's not like he'd be alone or that he wouldn't know anyone.
What would you guys do in this situation? Let it slide and let him bring a date, or put your foot down and be firm?