Family trip: wife's son fucks mother-in-law until she gets pregnant

“May I ask Daiki Kun… Will you ground me for a month before the trip?” Suddenly my father-in-law asked me, and I was confused. It was supposed to be a hot spring trip without family water, but my wife took advantage of me to be my mistress. However, my wife is not interested in having children and gets rejected no matter how many times I invite her. I was wandering around the motel room trying to appease the desires accumulated in the tank after abstinence when I happened to witness my mother-in-law's lewd bathing form...