Okay, I have spent the past few month stalking the etiquette boards to make sure I am doing everything right. Now, my FI (who knows very little of etiquette) thinks all of our guests should get plus ones. He has been talking to family members who said it is rude to not give EVERYONE a plus one, even if they are truly single. We are inviting people who have not been in any form of relationship (married, engaged, dating) for many years. FI thinks we should give everyone a plus one, because people will be offended if they are not treated like adults. I would honor a relationship if they were in one, no matter how soon they were dating, as long as it was before I have sent out the invites. You don't split up couples. However, we do not have the venue space for everyone to bring a plus one. They may not have a boyfriend or girlfriend, but they could invite a coworker, a friend, or a leprechaun, if they so choose. It would be ten times more rude not to have enough room for our guests who are invited than for people to bring just anyone to the wedding.... not to mention it would blow our budget to smithereens. Frustrated.