From eternalsoul's earlier post: "I said that our past sexual relationships with others has just been sex. Obviously. That's kind of how threesomes start and end. So I don't understand what you mean, but alright. "
Actually, poly threesomes seem to be really great friendships, that evolve into mutual sexual attraction. The friendship portion is, rather important. Really, how much time can you spend in bed? There's a lot of time left for talking, cooking, watching movies, swimming, playing on the beach, etc. --non-sexual activities.
Okay, maybe they don't start that way, but the friendship/relationship is the difference between Poly and a one night stand/swinging.