Non-monogamy is a type of interpersonal relationship in which sexual exclusivity is not held as the primary fundamental premise of the relationship. Individuals may form multiple and simultaneous sexual or romantic bonds. This can be contrasted with its opposite, monogamy, and yet may arise from the same psychology. The term has been criticized as it may imply that monogamy is the norm and that other ways of relating are deviations.
Many non-monogamous terms are flexible in definition, because they are based on criteria such as "relationship" or "love" that are themselves variably defined. In addition, usage creates distinctions beyond the raw definitions of the words. Thus, even though some relationships might technically be considered both polygamous and polyamorous, "polygamy" usually signifies a codified form of multiple marriage, based on established religious teachings, while "polyamory" is based on the preferences of the participants rather than social custom or established precedent.
Forms of non-monogamy include:
casual relationship a physical and emotional relationship between two unmarried people who may have a sexual relationship
cuckoldry, where a person has sex with another individual without the consent of their partner
group marriage (also termed polygynandry), in which several people form a single family unit, with all considered to be married to one another
group sex and orgies involving more than two participants at the same time
Line families, a form of group marriage intended to outlive its original members by ongoing addition of new spouses
ménage à trois, a sexual (or sometimes domestic) arrangement involving three people
open relationship (incl. open marriage), in which one or both members of a committed (or married) couple may become sexually active with other partners
polyamory, in which participants have multiple romantic partners
Poly families, similar to group marriage, but some members may not consider themselves married to all other members
polyfidelity, in which participants have multiple partners but restrict sexual activity to within a certain group
polygamy, in which one person in a relationship has married multiple partners
polyandry, in which women have multiple husbands
polygyny, in which men have multiple wives
plural marriage, a form of polygyny associated with the Latter Day Saint movement in the 19th-century and with present-day splinter groups from that faith. It is also associated with an evangelical splinter group which advocates Christian Plural Marriage
relationship anarchy, in which participants are not bound by set rules
swinging, similar to open relationships, but commonly conducted as an organized social activity
