There are variant forms of open marriage such as swinging and polyamory, each with the partners having varying levels of input into their spouse's activities.
The O'Neills describe open marriage as a relationship in which each partner has room for personal growth and can individually develop outside friendships, rather than focus obsessively on their couplehood and their family unit (being "closed").
Most of the book describes 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 might possibly include some forms of sexuality with other partners.
[5] There is a lack of content regarding studies and educational programming in open marriage and diverse relationship structures.
Common misconceptions of nonmonogamy[11] include that it violates principles of all religions, and that it is equivalent to polygyny (one man having multiple wives) or polygamy (a marriage of many).
[16] A 1981 study concluded that around 80 percent of people in open marriages experienced jealousy over their extramarital relationships.
Couples who prefer extramarital relationships emphasizing love and emotional involvement have a polyamorous style of open marriage.
Couples who prefer extramarital relationships emphasizing sexual gratification and recreational friendships have a swinging style of open marriage.
These distinctions may depend on psychological factors such as sociosexuality and may contribute to the formation of separate Polyamory and Swinging communities.
Polyamory is motivated by a desire to expand love by developing emotionally involved relationships with extramarital partners.
One factor may be sociosexuality,[33] an individual's willingness to engage in sexual behavior without having emotional ties to the sex partner.
Couples with different styles of open marriage tend to self-segregate in order to find others who share similar philosophies and interests, which has likely contributed to the development of separate polyamory and swinging communities.
Hunt mentions three general-population surveys conducted in the 1960s in which large majorities disapproved of extramarital sex under any conditions.
"[7] A 1975 study of several hundred men and women living in the midwestern United States found that 93 percent would not consider participating in swinging.
Studies in the 1970s found that engaging in sex with a greater number of partners increases risk of contracting sexually transmitted diseases.
[44] In a 1992 study, sexually transmitted diseases topped the list of disadvantages of swinging, and 58 percent of swingers expressed some fear of HIV/AIDS.
[45][46] A 1998 study found that the risk of sexually transmitted diseases can be greatly reduced by practicing safer sex.
[7][47][48][49][50] Studies in the 1980s found that couples report high levels of satisfaction and enjoy long-lasting open marriages.
[13][14][15] A 1995 study found that some couples drop out of the open marriage lifestyle and return to sexual monogamy.
[34][5][52] Blumstein and Schwartz note: Openly non-monogamous married and cohabiting couples often feel they are thought of as bizarre or immoral by the rest of their world.
(Blumstein & Schwartz, 1983, p. 294–295)>[5]Keeping their lifestyles secret reduces the amount of social support available to people in open marriages.
In 1983, Blumstein and Schwartz[5] determined that out of 3,498 married men, 903 had an agreement with their spouses allowing extramarital sex; of these, 24 percent (217 men) actually engaged in extramarital sex during the previous year, and overall 6 percent had been actively involved in open marriages during the previous year.
Hunt, based on interviews from a 1974 national study of sexual behavior, estimated that 2% to 4% of the married population was involved in open marriages.
[7]Hunt attributed the mistaken impression of increasing open marriages to a barrage of books, articles, and television shows dealing with the topic.
He also notes that speculative comments about increases in open marriage would sometimes be repeated often enough that people cited them as evidence.
[53]A large amount of media interest can mislead people into thinking the incidence of open marriage is on the rise.