Complex sentence: In 1974, after 12 years of imprisonment, Shih's first wife Chen Li-chu asked for divorce: she had an affair with one of Shih's friends, who was released before Shih.
Split into simpler sentences: In 1974, after 12 years of imprisonment, Shih's first wife Chen Li-chu asked for divorce. She had had an affair with one of Shih's friends, who was released before Shih.