Ore ga Kanojo o su Wake Episode 5

He had a person he once cared for, but she married his brother and soon gave birth to his niece... Over time his unrequited love distorted and changed him as he brooded on how the love of his life was stolen from him. One day his niece texted him asking to stay at his place because she wasn't getting along with her dad. She had done this before and he said it was fine, but this time he started to notice how much she had grown... in more ways than one... and that she also was the split image of his unrequited love... With his judgment clouded and his mind twisted he pulled out an aphrodisiac he had gotten from a vendor by chance and decided to make good use of it by putting it into his niece's drink... It wasn't long before he was able to have his way with her...