I Don’t Like Endings Where the Person who Cheats Gets Forgiven, so I Will not Forgive Her

“I can’t forgive all what she has done just because she apologized and made amends…” One day, about two years into their relationship, the protagonist Yukito catches his girlfriend, Yukina, cheating on him. Despite being together for over two years and having known each other since childhood, Yukito can’t bring himself to forgive her. At the same time, triggered by Yukina’s affair, the hidden feelings between Yukito and Yukina’s twin sister, Setsuna, start to surface.