New research shows that two factors are decisive in how often women initiate sex with their partners in a long-term relationship.
The first is women’s attitudes to casual sex, which may seem strange at first glance when talking about sex in long-term relationships.
“This measure describes how much women distinguish between the sexual aspects of a relationship and its relational and emotional aspects,” said Professor Leif Edward Ottesen Kennair at the Norwegian University of Science and Technology.
Women who tend to be more open to casual sexual relationships differentiate between positive, physical aspects of sex and relational and emotional aspects of a relationship. That means a quarrel about the dishes or who vacuumed last may not be as crucial to whether the couple has intercourse, the researchers said.
Often, whether a couple has sex or not is a compromise between the parties, and women who differentiate between sex and other aspects are probably more willing to compromise, he notes. Men are ready to have sex to a much greater extent, regardless of attitudes.
The other factor — passion — is much more important, according to the study’s findings.
“Passion in the relationship is of great importance for intercourse frequency,” said postdoctoral fellow Dr. Trond Viggo Grøntvedt at the Department of Psychology, who is the first author of the study, which was published in Evolutionary Behavioral Sciences.
For their study, the researchers considered several factors, such as how happy people are in their relationship, how committed they feel to their partner, how intimate they are, how much they trust each other, and the love between them.
Of all these factors, passion was the only one that could help predict the frequency of sex.
“Passion is actually the only one of these factors that matters. We didn’t find any association between any of the other aspects and how often people have sex in couple relationships,” Grøntvedt said.
The study included 92 couples between the ages of 19 and 30. Relationships varied in length from one month to nine years, with an average of just under two years. The couples had sex two to three times a week on average.
The longer the relationship had lasted, the less often the couples had sex, the study discovered. And one other factor, in particular, reduces the frequency, they say.
“Love is a commitment mechanism, and there is less passion and desire in a relationship if a partner is more interested in others,” Kennair said.
“Strong sexual fantasies about others than the partner don’t mix well with passion in the relationship,” added Associate Professor Mons Bendixen, also at the Department of Psychology.
“The most remarkable finding is, perhaps, that it’s only the woman’s attitudes to casual sex that affect the frequency of sexual intercourse,” said Kennair.
The findings may not apply to all cultures, Bendixen notes. They primarily apply to societies with more gender equality and female sexual control.