"Apparently it's My Fault That My Husband Has The Head of a Beast" is a fantasy romance manga that blends elements of comedy, drama, and supernatural intrigue. The story centers on Rosemarie, a young noblewoman who is married off to Claude, a duke cursed with the head of a beast. The curse stems from a tragic incident in Claude's past, where his first wife betrayed him, leading to his transformation. Rosemarie, unaware of the full extent of the curse, becomes determined to understand and break it, believing her presence might be the key to restoring Claude's humanity.

The narrative explores the evolving relationship between Rosemarie and Claude, highlighting their initial misunderstandings and gradual emotional connection. Rosemarie's cheerful and empathetic nature contrasts with Claude's brooding and guarded demeanor, creating a dynamic that drives much of the story's tension and humor. As Rosemarie delves deeper into the mystery of the curse, she uncovers secrets about Claude's past, the magical world they inhabit, and the true nature of the curse itself.

Supporting characters, such as Claude's loyal servants and Rosemarie's family, add depth to the story, providing both comedic relief and additional layers of conflict. The manga balances lighthearted moments with darker themes, including betrayal, loss, and the struggle for redemption. The curse serves as a central metaphor for emotional scars and the transformative power of love and forgiveness.

The plot progresses through a series of episodic adventures and emotional revelations, as Rosemarie and Claude navigate their growing bond while confronting external threats and internal doubts. The story's resolution hinges on whether Rosemarie's determination and love can overcome the curse, offering a satisfying blend of romance and fantasy. The manga's pacing and character development ensure that the central relationship remains the focal point, while the supernatural elements provide a compelling backdrop for the narrative.