In senior year of high schools, there were two girls, Sandy and Lisa, who thought of themselves as super-mature and sophisticated and liberated in sexuality and relationships. They had boyfriend's, and then decided to swap, and were very exhibitionist about it, making it known that they had swapped partners.
Except Sandy was happy with the 2nd boyfriend, and Lisa wasn't--Lisa wanted to go back to the original arrangement. Sandy and Lisa had a short fight over, and Sandy won.
After the fight, both of the guys wanted Sandy. Lisa got shunned by the girls in the school after that, and didn't go out much.