Three years after we got married, my wife became pregnant. Her wife said she would give birth at her parents' house, so she decided to return home. I thought it was okay to be single for the first time in a while, but then my wife's sister came to help her with the housework. I met my sister-in-law for the first time in a while and she seems cute, and her figure is nice and attractive, so even though I think she's no good, I still see her as a woman. I feel uneasy when I think of being alone in the same house.