So my fiance and I have decided not to really do any +1. I don't feel bad about this because everyone we're inviting will know at least a few friends, so no one will be left with no one to talk to.
My issue is that I have a ton of cousins that I'm not sure if they have SOs or not. If they do (we live in different states, so it's very possible that I've never met them and I can't trust FB), I want to make sure they're invited.
Is there a nice way to ask if someone is in a relationship without them thinking that they're getting a +1?