Social compartmentalization: A theory

'After we had sex, our relationship changed," she said. Statements like those have been uttered millions of time over the decades and perhaps centuries.
Things were going so peachy between the two of you; sex seemed to mess it all up. Evr felt like that?
If so then you have probably stumbled upon the rationalization of compartmentalization.
Compartmentalization means fractionalizing your relationships into compartments.
This is all heady stuff, but if you think about it, it all stems from the basic social unit we all know and love: family.
Every other relationship is an offshoot, and derivative of that one. But because of our need (or lack of) family we compartmentalize our friendships.
Where there used to be just boyfriends and girlfriends (pre-cursors to husbands and wives), now there are cut-buddies, and simply hookups, "friends with benefits," etc.
So, as you sit and realize that you just had sex with a big playboy bunny, it all seems to sink in, we're all trying to get family, or what's familiar to us.
It all gets complicated after sex, doesn't it?
The questions are many: "Are we friends ... or lovers ... or was it (gulp) jes sumptin ta do?
The crux of the matter is: Do you have compartments for your friends?