So, here's the deal. I did individualized RSVP cards so there would be no confusion as to who is invited. FI told me that his cousin wants to bring someone. Of course fiance made the guest list for the people on his side. He didn't mention his cousin having a SO. Now he says that the cousin has an on again off again SO. Do I say sure let the cousin bring the "SO"? Is it wrong to make an exception and allow the cousin bring someone?