He says he started having sex with his younger sister after her husband died and his wife and him invited her to live at their place and in return she could help his wife with their 5 kids. But after some time she was also hwlping his wife in a way she didn't know. He likes to have sex everyday but his wife not so much so his sister came to save the situation and everyone is happy. His wife thinks he got his sexual appetite under control but the truth is that his sister is helping him on that.