Do we have to invite every guest with a partner or ‘plus one’ even though we know they are single?

If a guest isn’t married or in a serious relationship, then it’s perfectly acceptable to invite them without a partner. If a guest RSVPs for two when you have only invited that person on their own, you will need to explain that you’re having an intimate wedding and unfortunately, are not able to invite everyone with a guest.

Maybe to avoid any uncomfortable situations, extend a plus-one invitation to your single friends and family anyway, that way they can decide whether to bring a partner along or not.