Soooooooo your cousin wants a plus one…so does your friend from high school…and your thrice divorced aunt…and your sister who has been dating her boyfriend for less than a week. What do you do?
It depends! If you’re having a small event then it makes a big difference to go from very intimate guest list to also including their random friends or dates. Especially in these COVID times where venues are adding restrictions for the amount of guests you can have at your event. You’re also shelling out a certain amount of money per person in attendance to your event. You want your friends and family to have fun but at the same time its your day, its your party, and sometimes you have to just put your foot down.
My own rule of thumb is if they’ve been dating for at least 6 months and you've actually met their partner then it is safe to include them as a plus one, I do not generally encourage the just open plus one situation unless you have those funds in your budget! Its fun to have a big party and to let single people plan on bringing a friend to dance and have fun with, but you should not feel obligated to allot a plus one slot for single people or even people in relationships. Those that are married it is traditional to be sure to invite the spouse of your intended guest but even there depending on the size of your event or your relationship with that person there are exceptions to every rule.
The biggest thing to remember is that your wedding day is about you! You need to do what will make your event enjoyable for you; and your friends and family are there to support you on this huge life step they can go one night without a date if that is what makes the most sense for you on your night!