'Love Affair' Yoo Ah In directly showed his love for his teacher Oh Hye Won, played by Kim Hee Ae.

On the third episode of the cable channel JTBC's "Love Affair" which aired on March 24, 2014, Lee Sun Jae, played by Yoo Ah In, called Oh Hye Won his teacher. When Oh Hye Won corrected him and said his teacher is her husband, professor Kang Joon Hyung, Lee Sun Jae said, "You are my teacher. Nobody was interested in me when I would deliver packages at my part time job. But you said you wanted to listen to my music more, you observed what kidn of a person I was, and you even played with me." Lee Sun Jae later at home told his online friend about Oh Hye Won. The friend, who happened to be Oh Hye Won, realized Lee Sun Jae's love for her, and did not know what to do. the day after, Lee Sun Jae encountered his mother's death, and did not go to the college to take the entrance exam. Later, he left his life in Seoul to work as a postman. He decided not to go to music school or pursue a career as a pianist because his mother had lost her life while coming back home after buying hand warmers for him early in the morning, because he complained the night before that there was not any in the house. Lee Sun Jae felt guilty at his mother's death and sold the house, and gave up going to college.

In related news, cable channel JTBC's new drama titled "Love Affair" is a story of a forty something woman, Oh Hye Won, who is played by actress Kim Hee Ae, and a naïve genius pianist Lee Sun Jae, played by actor Yoo Ah In.