Associated Polyandry
A form of polyandry known as associated polyandry refers to any system in which polyandry is open to men who are not necessarily brothers (Levine and Sangree 1980). There is some evidence that associated polyandry was an acceptable marriage variant in parts of the Pacific and among some indigenous peoples of North and South America. The best-described form of associated polyandry, however, is from Sri Lanka. Among the Sinhalese of Sri Lanka, a woman may marry two men, but rarely more than two. Unlike fraternal polyandry, which begins as a joint venture, Sinhalese-associated polyandry begins monogamously. The second husband is brought into the union later. Also unlike fraternal polyandry, the first husband is the principal husband in terms of authority. A woman and her husbands live and work together, although economic resources are held independently. Both husbands are considered fathers to any children the wife bears.

This system allows many individual choices. For example, two husbands and their wife may decide to take another woman into the marriage"often the sister of the wife. Thus, their household becomes simultaneously polygynous and polyandrous, a marriage pattern called polygynandry. Thus, depending on relative wealth and the availability of economic opportunity, a Sinhalese household may be monogamous, polyandrous, or polygynandrous.

As we mentioned at the beginning of the chapter, one important aspect of marriage is the creation of ties between the bride"s and the groom"s families. The two forms of polyandry just discussed sharply curtail the potential network of ties created by marriage. This is particularly true where fraternal polyandry occurs with preferred or permitted sororal polygyny. For example, in a Tibetan household of four brothers married to one woman, the entire household is tied affinally only to the family of the wife. If these same brothers take another wife by marrying a sister of their first wife, they would be giving up the possibility of establishing ties with other households in favor of fortifying the relationship already established by the first marriage. Nancy Levine and Walter Sangree call this alliance intensifying (1980).

Secondary Marriage
Another form of polyandry, sometimes referred to as secondary marriage, is found only in northern Nigeria and northern Cameroon. In secondary marriage, a woman marries one or more secondary husbands while staying married to all her previous husbands (Levine and Sangree 1980, 400). The woman lives with only one husband at a time, but she retains the right to return to a previous husband and to have legitimate children by him at a later date. No divorce is permitted in the societies that practice secondary marriage; marriage is for life.

In this system, men are polygynous and women polyandrous. A man marries a series of women and lives with one or more of them at his homestead. At the same time, the women independently pursue their own marital "careers." Secondary marriage is really neither polyandry nor polygyny but rather a combination of the two, resulting from the overlap of men seeking several wives and women seeking several husbands. Secondary marriage is the opposite of Tibetan fraternal polyandry. It is alliance proliferative, serving to connect rather than to concentrate groups as people build extensive networks of marriage-based ties throughout a region.