Are one night stands really partner status?
as in "sexual partner" versus "Significant Other partner", I think.
you can have a partner for a one-time thing, or multiple partners concurrently that are all "transactional" for want of a better term (people you meet up with for a single instance of intimacy but with no recurring obligations after that point).
Think of it like "oh I need a dance partner for the night", but it doesn't have to be your SO.