Study: Friends With Benefits (FWB) = Stress

"Removing all the "stat speak" from that paragraph, it boils down to 10% evolved into a traditional relationship, about 33% stopped the sex but continued as friends, 25% ended both the sex and the friendship, and 32% continued as FWB...The study concluded, according to Dr. Timothy Levine, one of the study's authors, 'that people got into these relationships because they didn’t want commitment. It was perceived as a safe relationship, at least at first. But also that there was this growing fear that the one person would become more attracted than the other.' Leading to the same stresses and problems seen in traditional relationships."

http://www.thebachelorguy.com/any-benefit-to-friends-with-benefits.html