Swinging is not polyamory, and the difference is often a sore spot when poly people are speaking with non-polys about what polyamory is. Swinging is generally recreational sex with little emotional involvement. Swinging is typically done by couples attending special swing venues or parties together. Swinging communities often have rules, explicit or implied, against falling in love with others in your swing group.
Sometimes people who swing tire of sex for its own sake and wish for more personal and intimate connections. Two or more couples who swing together frequently may simply grow to become close life friends and/or desire more. In either case, people may find themselves drifting away from swinging and into the wonderful and challenging world of polyamory.
Conversely, polyamorists can be swingers too, happy to enjoy an occasional no-strings fling at a party or sex club. But the two circles tend to be different in terms of sociology, class, philosophy, and intellectual background. Many polys shun swinging because of negative connotation associated with it. The mainstream attitude is that swinging is wrong and immoral; the mainstream attitude toward polyamory is similar, but polys usually resist being stigmatized as caring only about sex.
A group could be an open triad with a relationship agreement stating that swinging is OK, and one or more of the participants engages in swinging. The triad relationship would still be polyamorous, but the relationship with the outside swinging partners would not necessarily be.
originally published © http://knol.google.com/k/james-o-neill/polyamory/3czmgkncteg8o/2