These ambiguities can be avoided to some extent (albeit at the price of venturing into less normative territory), by comparing the relationships of polyamorous couples to the relationships of couples into the swinging lifestyle. Both types of relationships involve sexual interactions with people outside of the dyad, but they differ in the emotional component of the interactions. Specifically, the extra-dyadic relationships of polyamorous couples often include both sexual and emotional components (Constantine & Constantine, 1971; Knapp, 1976; Rust, 1996), whereas the extra-dyadic relationships of swinging couples typically include only a sexual component (Denfield & Gordon, 1970; Fang, 1976; but see Symonds’, 1971, discussion of utopian swingers and Varni’s