This is one of the sinister notions that propels many AIDS
s. It's not literal, of course. It just means that every time you have unprotected sex
with someone, you leave yourself open to the risk of receiving all sorts of nasty STD
s from that person with the idea that the next time you have sex
with another partner
, you are very likely passing those diseases to your partner, indirectly as if they had slept with your previous partner.
I kinda agree with it conceptually, so I'm not gonna make any comment on it.. (I hear a dozen sighs of relief)