This is not a matter of yeonwu being too innocent or stupid, the guy has a really low self-esteem, that's why even tho Taehwan is an asshole most of the time he still doesn't care and he forgives him, yeonwu likes the attention and the thought of being wanted by the hottest guy in college/his crush. He's just a lonely guy who wants to be loved and that's why he likes everything Taehwan does to him
As a someone who experienced sexual assault is really awful seeing y'all blaming taehwan about "not going to therapy"... He's a victim and accepting that something like that happened is really hard