Haruki hears about Kazusa's moving from her mother, who she hadn't been on good terms with.  He feels betrayed and angrily confronts her.  But his words force open the door to Kazusa's heart, which she had desperately tried to keep closed so that the three of them could stay together.
Is that all I've ever been to you?
Ist das alles, was ich 
dir jemals bedeutet habe?
¿Eso es todo lo que significaba?
¿Todo lo que alguna vez he podido significar?
Je ne représente 
rien de plus pour toi ?
Eu não sou nada para você?