In The Male Couple: How Relationships Develop, psychiatrist David P. McWhirter and psychologist Andrew M. Mattison (themselves a ‘gay’ pair) authored the results of a study of 156 males in homosexual relationships lasting from one to thirty-seven years. They reported:...Only seven couples have a totally exclusive sexual relationship, and these men all have been together for less than five years. Stated another way, all couples with a relationship lasting more than five years have incorporated some provision for outside sexual activity in their relationships....That means that only 9 percent of the male partners were actually monogamous, and none of the relationships lasting more than five years were sexually exclusive.