The document discusses various forms of non-monogamous relationships including polygyny, polyandry, swinging, open marriages, polyfidelity, and more. It provides examples of polygynous family structures from several cultures including the Luo people of Kenya, Maasai people of Kenya and Tanzania, and Huli people of Papua New Guinea. The document notes some benefits of polygyny for both men and women, and discusses factors that can cause jealousy among co-wives as well as challenges faced by different family structures.