..have you even played the game? There is no NTR in this game.. it just allows you to be submissive or dominant depending on your preference
It's been a while, but i'm pretty sure I remember both your sister and the blonde girl fucking other people, even if you are opposed to it, one of them even does it after you've mind controlled her to only be attracted to you lol. Or are you one of those people that doesn't consider it NTR if you're not married to the girl and haven't performed a blood ritual to be spiritually bound together -__-.
Also isn't the mom also cheating on your dad with another guy lmao? I'm not sure about this one, don't remember