"And I am no longer keeping any memories. From now on, I will never give away my love." -- Zhoumi, Goodbye 

He swore that he would forget about her, and he seemingly did, becoming closer with many other artists, some females but, he never got in another relationship.  That was because he promised he would never give away his love again, not after Yoona.  He never kept any memory of her, but it was hard, she was a well-known model, always brought up by others for her beauty.  But he ignored it, and with time he forgot about her, and she somehow forgot about him.