Researchers have found a potential new source for sexual problems among middle-aged and older men: The relationships between their female partners and the men's closest friends.

Cornell University and University of Chicago researchers have found a connection between erectile dysfunction and the social networks shared by heterosexual men and their partners. The researchers describe the situation as "partner betweenness." In such cases, a man's female partner has stronger relationships with his confidants than the man does - in effect, the romantic partner comes between the man and his friends.

"Men who experience partner betweenness in their joint relationships are more likely to have trouble getting or maintaining an erection and are also more likely to experience difficulty achieving orgasm during sex," write Benjamin Cornwell, Cornell professor of sociology and Edward Laumann, University of Chicago professor of sociology in the paper.

Cornwell and Laumann argue that partner betweenness undermines men's feelings of autonomy and privacy, which are central to traditional concepts of masculinity. This can lead to overt conflict or problems with partner satisfaction and attraction. They examined data from the National Social Life, Health and Aging Project, a comprehensive survey at the University of Chicago that included 3,005 people, from ages 57 to 85. The project is by supported by the National Institutes of Health.

The research, "Network Position and Sexual Dysfunction: Implications of Partner Betweenness for Men" is published online today, Aug. 8, 2011, in the current issue (dated July 2011) of the American Journal of Sociology. [NOTE: The paper issue of the journal will be published in late August 2011.]

Laumann said the study shows the value of understanding the connection between social relationships and health. "The results point to the importance of social network factors that are rarely considered in medical research - network structure and the individual's position within it."