Explain the sad story of Phedon.

His best friend told him a lie about his fiancee being unfaithful to him. He even told him where to see her performing her lewd act with another man. Later, he took a young servant girl and made love to her where Phedon would see them and think it was his beloved. Phedon was so outraged by this unfaithfulness that he killed her when he next saw her. When he was later told about his friend's betrayal, he killed him too.