Also when me and my wife first started living together she tried to pull this argument on me. So I said to make it 100% fair each time one of us uses the toilet put both the seat and lid down. And if we forget and are called out on it we put a dollar in a small jar with the other person's name on it. That lasted about 3 weeks till she got tired of it and there was enough money in my jar to buy her a random gift. I spent my jar money on her. She is still puzzled to this day why I did.