The social cost of falling in love: Gain one lover---lose two friends?

A fascinating news report coming out of the British Science Festival in Birmingham confirms the tried and true saying: You can't have it all. Specifically, you can't fall in love with a new romantic partner and simultaneously juggle ALL your close friends, which typically average five in number.

Single women often complain that their girlfriends, who were once as close as sisters, dump them when they find a new guy. They're left hurt, upset and bewildered. Whatever happened to sisterhood, they wonder?

Based on this report, however, it seems to be a matter of simple arithmetic: You can't add a consuming new romance and keep your other tight-knit relationships at the same number and level of intensity---and this phenomenon isn't limited to women.

British anthropologist Robin Dunbar and colleagues at Oxford University administered a web-based questionnaire to 428 women and 112 men (between the ages of 18 and 60) to learn how participants balanced a new romance, with existing relationships with family and friends. In a paper submitted to the journal Personal Relationships, the research team found that men and women are equally at risk of losing two close friends when they get involved with a new romance. After that, they're left with four remaining friends, on average, one of them being the new person that has come into their life.

In another news report, Dunbar playfully makes the point that it isn't personal. "You can only have five slots for deeply intense and meaningful relations. Those individuals don't have to be human. They can be your dog - or your favourite chrysanthemum plant. They can be people in an entirely fictional world - they can be soap opera characters. They can be God or they can be saints," he says.

I'm curious whether people who lose friends under these circumstances are able to recover neglected friendships (or add others) as their romances mature. Perhaps, these losses are transitional, fueled by raging hormones that cloud judgment. In any event, this study is an intriguing reminder of how fragile friendships can be when someone you know is in the throes of a new love.

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Irene S. Levine, PhD is a freelance journalist and author. She holds an appointment as a professor of psychiatry at the New York University School of Medicine. Her recent book about female friendships, Best Friends Forever: Surviving a Breakup with Your Best Friend, was published by Overlook Press. She also blogs about female friendships at The Friendship Blog and at PsychologyToday.com.