ef - a tale of memories - 1x11 - Season 1, Episode 11- Followmy.tv

Chihiro finishes her novel and wants Renji to read it, though does not want to be around when he does. Renji proposes they go out on a date, which Chihiro happily agrees to, though she promises Renji that they will become lovers for only one day. After their date, Renji confesses his love to her once again on the school balcony, and shortly after they have sex. Later that night, Chihiro gives Renji the novel to read, and she goes up to the school balcony to wait for him to finish. After realizing the bleak ending of the novel, Renji runs up to the balcony to meet Chihiro, though she tells him that they should break up while she can still say "I love you" and fully mean it. Chihiro throws all her diary pages containing accounts of Renji into the air, effectively forcing Renji to break up with her.