as sociosexuality and may contribute to the formation of separate Polyamory and Swinging communities. Despite their distinctions, however, all open marriages share common issues: the lack of social acceptance, the need to maintain the health of their relationship and avoid neglect, and the need to manage jealous rivalry. Many open couples establish rules that forbid emotional attachment, extramarital children, extramarital sex in the marital bed, extramarital sex with those known to both partners, or extramarital sex without the use of barrier contraception. Some open marriages are one-sided. Some situations giving rise to this are where the libidos of partners differ greatly, or illness renders one partner incapable of, or no longer desiring, sex. The couple may remain together while one partner seeks out sexual gratification as he or she sees fit. The difference between these situations and a cheating situation is that both partners in the marriage are aware of, and agree to the arrangement. Types of openness: from "polyamory style" to "swinging style" Extramarital relationships vary in terms of the degree of sexual involvement desired and the degree of emotional involvement desired. Presented with the potentiality of non-monogamous intimacy, a given individual might be motivated more either by the desire for multiple sexual partners or a wider erotic experience than offered by monogamy, or by the desire for multiple others with whom to form an emotional or familial bond. Polyamory is motivated by a desire to expand love by developing emotionally involved relationships with extramarital partners. Swinging is motivated by a desire for physical gratification by engaging in sexual activities with extramarital partners. The distinction between polyamory and swinging applies to open marriages. Delineation of polyamory and swinging has appeared in academic literature, popular media, and Web sites devoted respectively to polyamory and to swinging. (The swing sites prefer to frame the distinction more along Gould's "utopic swingers" and "recreational swingers".) A polyamorous style of open marriage emphasizes the expansion of loving relationships by developing emotional attachments to extramarital partners. A swinging style of open marriage emphasizes physical gratification by engaging in recreational sex with extramarital partners. Psychological basis The preference for a polyamorous versus a swinging style of open marriage may depend on many psychological factors. One factor may be sociosexuality, an individual's willingness to engage in sexual behavior without having emotional ties to the sex partner. Individuals who are very willing to engage in sexual behavior without