[Enforcing monogamy and restricting Extra-marital sex is how religion and Authoritarianism suppress sex, which creates Violence. You would have to wonder how much Prostitution, Porn, and the fallout from Extra-marital sex (divorce, child abuse) are caused by enforced by law monogamy.]
See: Violence Premarital sex
[2012 Sept] Polyamory: Three’s (or four’s, or five’s) company
 Sexual Monogamy & Violence Against Woman - A Betrayal of Human Sexual Evolution by James Prescott Stephen Lowman of The Washington Post commented that: “Humans weren't wired to be monogamous, contend the authors, and until about 10,000 years ago most had multiple sexual partners. The agricultural revolution and the concept of private property placed new pressures on the roving eye, but our innate biology has not changed with our social institutions.”
 THE TRUTH ABOUT SEXUAL MONOGAMY by James W. Prescott, Ph.D.
The Fundamental Slavery by Osho
Adult Spirit - West. Physical: Needs an open and unlimited sexual circle; needs to be able to make that choice: celibate, monogamous, triadic, expanded, or polygamous freely.  Sacred Wheel Teachings and Self-Development Techniques by Swiftdeer
"Prisons are built with stones of Law, brothels with bricks of Religion." -William Blake
"Sexually awakened women, affirmed and recognized as such, would mean the complete collapse of the authoritarian ideology" ----Wilhelm Reich ("The Mass Psychology of Fascism" and "The Function of The Orgasm").  THE TRUTH ABOUT SEXUAL MONOGAMY by James W. Prescott, Ph.D.
Specifically, in my study of primitive cultures, I found the following statistically significant social-behavioral characteristics of cultures that punished pre-marital and/or extra-marital sex: 1) slavery is present; 2) low female income; 3) personal crime is high; 4) kin group is patrilineal; 5) wives are "purchased"; 6) sex disability is present; 7) intensity of sex anxiety is high; 8) castration anxiety is high; 9) bellicosity is extreme; 10) military glory is strongly emphasized; 11) killing, torturing and mutilation of enemy captured in warfare is high; 12) a high god is involved in human morality; and 13) supernaturals of the culture are aggressive and violent.  THE TRUTH ABOUT SEXUAL MONOGAMY by James W. Prescott, Ph.D.
Love must be spontaneous to be a spiritual bond in the beginning,
and it must remain spontaneous if it is to remain spiritual...and
those of us who do not believe in the possibility of free love ought
to declare frankly that we do not, at bottom, believe in the
possibility of freedom.
Winds of Doctrine (1913)
"Christian missionaries to Africa condemned polygamy, with the result that great numbers of women became "socially superfluous". Many went to the cities and became prostitutes. Missionaries to North America had a similar effect when, discovering the informal family arrangements between many white settlers and native American women, they accused the natives of immorality and prostitution. Protestant women in pioneering settlements adopted the missionary position - or rather, supported the missionaries' point of view - with the result that Indian women lost the status and respect they had enjoyed from the earlier white settlers. Interracial marriages died out, while prostitution flourished".--Love for Sale: a global history of prostitution by Nils Ringdal
Available data clearly indicate that the rigid values of monogamy, chastity, and virginity help produce physical violence. The denial of female sexuality must give way to an acceptance and respect for it, and men must share with women the responsibility for giving affection and care to infants and children. As the father assumes a more equal role with the mother in child-rearing and becomes more affectionate toward his children, certain changes must follow in our socioeconomic system. A corporate structure which tends to separate either parent from the family by travel, extended meetings, or overtime work weakens the parent-child relationship and harms family stability. To develop a peaceful society, we must put more emphasis on human relationships.  BODY PLEASURE AND THE ORIGINS OF VIOLENCE By James W. Prescott
It is the variable of carrying the infant on the
body of the mother/caretaker in primitive cultures that is so strongly
predictive (80%) of peaceful and non-violent cultures which includes lack of
abuse of infants and children.
When the infant physical affectional variable was combined with permitted pre-marital sexuality my prediction of peaceful or violent cultures rose to 100% of the 49 cultures where this information was available. Further, these cultures were matrilineal where 78% of the nine cultures that also had information on extramarital sexuality also permitted extramarital sexuality.
The ultimate human spiritual-sexual state, however, can only be realized when the human female (whose brain is uniquely designed for the spiritual-sexual state) is completely free to express her sexual love according to her own terms which means multiple sexual relationships without fear of male reproach, control or violence. For this to occur the developing brain of the infant/child must be encoded and programmed with pleasure (affectional bonding) for the neural circuits to develop to make possible the spiritual-sexual state later in life. Unfortunately, just the opposite is happening in most human cultures of today where infant/day care centers, e.g., provide little or no affectional bonding with anyone.
If the human male was wise (which he is not) he would realize the significance of affectional bonding throughout life and that he would be an extraordinary beneficiary of this new affectional-sexual-spiritual path.
Although, THE TAO and TANTRIC BUDDHISM represent the most enlightened of the patriarchal cultures, particularly, with respect to human sexuality they are significantly limited because of their subordination of women to men and their conceptual errors concerning the truth of female spiritual-sexual energy. The extraordinary insights of Wilhelm Reich is partially corrective to these errors, e.g. "Sexually awakened women, affirmed and recognized as such, would mean the complete collapse of the authoritarian ideology" (see "The Mass Psychology of Fascism" and "The Function of The Orgasm").
The correct view is that human sexual-spiritual development must follow the path of the feminine and that is why Teilhard de Chardin stated: "Woman is, for man, the symbol and personification of all the fulfillments we look for from the universe... The feminine is the most formidable of the forces of matter." (The Evolution of Chastity.)  THE TRUTH ABOUT SEXUAL MONOGAMY by James W. Prescott, Ph.D.