Sex education in immorality: My mother-in-law's mischief

Miko brought her dad six months ago. A young, beautiful woman, two years older than her father... Miko began living in this house and eventually became my stepmother. I think it was going well at first. However, after that night, I no longer could recognize Miko as my stepmother. Miko gets mad after having sex with her father. That appearance is burned into my mind and I can't leave it.