Title Mitei No Prologue

Title Mitei No Prologue summary:

In the class of Nanami Yuki, a senior in high school, there was a man like a sanctuary, Hachida Momoru, who had an aura that kept people away from him. One day, Nanami happens to pick up a notebook that he always writes in and discovers that it contains a novel. Shocked by the contents, Nanami visits Mamoru's house to tell him how he feels about it, but there he finds him in the arms of a man who is far removed from the image of sanctuary... As he agonizes over this, Mamoru asks him to pretend to be his boyfriend in order to break up with the last man...