The origins of the term open marriage remain obscure. Researchers in the 1960s used the term open marriage to describe individual freedom in choosing marriage partners.[1][2] Closed marriage meant individuals had to marry someone based on social prohibitions and social prescriptions. Open marriage meant individuals could choose to marry someone based on personal preferences.
Nena O'Neill and George O'Neill changed the meaning of the term with the 1972 publication of their book Open Marriage, which sold over 1.5 million copies. The O'Neills conceived open marriage as one in which each partner has room for personal growth and can develop outside friendships. Most chapters in the book dealt with non-controversial approaches to revitalizing marriage in areas of trust, role flexibility, communication, identity, and equality. Chapter 16, entitled "Love Without Jealousy", devoted 20 pages to the proposition that an open marriage could include some forms of sexuality with other partners. These concepts entered the cultural consciousness and the term "open marriage" became a synonym for sexually non-monogamous marriage, much to the regret of the O'Neills. In the 1977 publication of The Marriage Premise, Nena O'Neill advocated sexual fidelity in the chapter of that name. By then however, the concept of open marriage as sexually non-monogamous marriage had gained a life of its own.
Today, with many committed couples not seeking formal marriage, the term is frequently generalized to 'open relationship' or 'responsible non-monogamy'.
WHAT ABOUT THE LAST SENTENCE?