A prosperous father-in-law and a capable daughter-in-law

The story is about a family, the daughter-in-law is lustful, the father-in-law who lost his wife early is also extremely horny. Even though he is old, he still likes his young daughter-in-law. One time, when she was bored with her husband, the two naturally came together, pounded each other and slept together like that. That bland husband had no idea that his wife was having incest with her own father. What  happened.