Lesbians may engage in "open" relationships where they agree to have relationships with more than one person at a time.
Another example of a polyamorous relationship might be a married couple, where one member is bisexual and both agree that she can have relationships with other females.
Being unfaithful or cheating are NOT considered polyamory.
HistoryIn the 1970s through early 1990s many lesbian feminists practiced polyamory (non-monogamy) claiming that monogamy was part of the patriarchy and part of male ownership and control over women's sexuality.
Sources: Serolynn.com, M. Black