義母散華～ははさんげ～

Koga Tomonori is an ordinary college student and the only son of a typical middle-class family. A year and a half after losing his biological mother to an incurable illness, his father remarried a beautiful stepmother, Hanae, and together with her daughter, Marie, they’ve been living a relatively happy life.

But one day, Tomonori discovers a shocking truth: his father, Seiichi, had been cheating on his late wife for years — and the other woman was none other than his current stepmother.

Tomonori had always resented his father, blaming him for his mother’s death. He believed her illness worsened because his father neglected the family. Yet he’d also tried to convince himself this resentment was misplaced — that his father must have grieved too. But he was wrong.