The rise of "bromance" is threatening heterosexual relationships as men increasingly find more emotional satisfaction from their friendships with close male friends than their relationships with women, academics at the University of Winchester have warned.
All the men involved in the study had had "bromantic" friends who they lived with, and had known for at least 18 months.
Of the 30 men, 29 said they had cuddled with another guy, and many said they often shared a bed.
Study authors Robinson et al. interviewed 30 undergraduate straight men.
"Given that young men are now experiencing a delayed onset of adulthood, and an extended period of adolescence, men may choose to cohabit as a functional relationship in the modern era", said Dr Robinson.
"With a romance", the men griped, "one was constantly posturing and self-monitoring", acting, "the part of the adoring boyfriend", in order to sleep with their girlfriends, researchers found. "Everyone knows it, and nobody is bothered by it because they do it as well".
Another man surveyed, called "Martin" said: "It's like having a girlfriend, but then not a girlfriend".
One man, "Harvey", said he didn't even feel comfortable divulging that he loves listening to Beyonce and Taylor Swift - for fear that his girlfriend would judge him.
Moreover, it was easier for them to overcome conflicts and express their emotions in their bromances than in their romances.