Polyandry is a form of plural marriage in which one woman has multiple husbands. While it is a much rarer marriage tradition than polygyny, the practice has been found in numerous cultures, most prevalently in the form of fraternal polyandry where two or more brothers share the same wife. This fraternal marriage system ensures a single line of heirs with rights to paternally descendant property and wealth, rather than the multiple lines of inheritance that would result from each of the sons of a family starting families of their own.
It also ensures that resources are focused around one set of progeny, and with multiple working men to support this set of children, increases the chances of survival of future generations. This practice is typically characterized as the product of extremely scarce resources combined with low female birth rate.
Unlike polygamy, polyandry is not typically sanctioned by any government or religion, but rather exists as a cultural practice. In Tibet, where polyandry was once widely practiced, the marriage system has been rendered illegal by the Chinese government, although regulations are typically not enforced. Enforcing laws about group marriage is notoriously difficult when practitioners do not live publicly in cities, and so the practice continues in many areas without legal benefit or consequence.
Like all systems of human commitment, polyandry does cause a number of common conflicts for its practitioners. When children of plural fathers ask who their specific father is, they are typically told that all their fathers are equally responsible. This is not a problem in polygyny, where the child's primary mother is obvious.
Many wives in this type of arrangement also admit to issues with jealousy among husbands, though they also pride themselves on the ability to work out these issues within the marriage. Since this is an enduring practice in many cultures, most engaging in this behavior have a wealth of community resources available to help them deal with these issues.
Media characterizations of polyandry often attempt to portray practitioners as sacrificing love for tradition and survival in harsh conditions. These portrayals often do not acknowledge that polyamorous relationships exist voluntarily in many Western countries, and though these arrangements are not recognized by law, they are mainly entered into freely and often involve multiple men who are faithful to one woman for extended periods of time.
That is to say, a form of long-term commitment similar to polyandry exists in Western cultures. This marriage structure exists because it works for some situations both emotionally and economically.