It never said. It only said that his main reason for not dating was that he wanted to focus on his career. Honestly, I don’t think even YiYun knows, because I don’t think he ever had a crush or ever had any interest in dating to begin with. This is probably a new area for him.
Is Yiyun originally like men? I need to reread this manhua again so I can see cutie little Rorou more(づ ̄ ³ ̄)づ