"Falling in love comes at a cost that does not include flowers or bar bills. In the first experiment of its kind, scientists have discovered that starting a romantic relationship typically costs two close friends from the inner circle of intimate contacts that most people rely on for support and advice. The study, led by Professor Robin Dunbar of Oxford University, was part of research into the social networks that most people build up over their lifetime. These networks typically consist of a maximum of about 150 friends, family and acquaintances, with only about five, on average, belonging to the 'inner circle'."