Ore ga Kanojo o su Wake.

Ooki Ryuuji used to have someone he liked. That person ended up marrying his brother and giving birth to a child. His feelings distorted with time as he buried them deep within his heart. Rinka, the child of his brother, came to him after she ran away from home. She has such a nice face... She grew up to be just as pretty as her mother. Reaching puberty, she's gained volume in her breasts and thighs that show through her sailor uniform. The feelings in Ryuuji resurface seeing Rinka who resembles her mother so much. His logical side completely breaks down after coincidentally finding an aphrodisiac. “I have known this girl since she was born. She looks just like the girl I liked and has a really nice, mature body… I can tell that I won’t be able to hold myself back for long.”