Originally Posted by Kittywitch
. . . the thought of a quad, where everyone is dating everyone else . . .
A quad just means four people in relationship with each other. It could be
all people involved sexually with each other, but doesn't have to
. Any combination of the four can be sexual with each other and the other(s) can just be part of it without the sex. I would guess that more often than not, a quad would tend to be a "wife swap" situation, but that's just a guess and totally unfounded on anything.