For centuries, the Judeo-Christian moral code has defined the official relationship standard in western-society – the monogamous relationship:
- monogamy, an exclusive relationship with one partner.
There are quite a number of variations on the ‘standard’ monogamous relationship. The blanket term is non-monogamy. This phenomenon is also defined as polyamory, in which participants have not one but multiple romantic and/or sexual partners. Forms of non-monogamy include:
- infidelity, in which a person has a sexual ‘affair’ outside of an otherwise monogamous relationship;
- casual relationship, an emotional relationship between two unmarried people who may also have a sexual relationship;
- open marriage, in which one or both members of a committed couple may become sexually active with other partners;
- swinging, several open relationships which are commonly conducted as an organized social activity;
- ménage à trois, a sexual (or sometimes domestic) arrangement involving three people of either sex;
- orgy (also known as, a sexual relationship involving more than two sexual participants at the same time;
- polyfidelity, in which participants have multiple partners but restrict sexual activity to within a certain group;
- polygynandry (also known as a group marriage), in which several people form a single family unit, with all considered to be married to one another;
- 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.
