第9話: 過去のカズキの恋人たちを知ったユウジは嫉妬を覚える

9

Yuuji gets told that Kazuki was popular among guys in middle school and was proposed to by many, but refused all for an unknown love of hers. Yuuji thinks it's the new teacher, who she and Chihaya know, which causes him to start feeling jealous. (Source: Wikipedia)