In the film, Shiro's husband is difficult or scolds his wife, especially he doesn't like to "go to bed". Tadashi's father always defends his daughter-in-law every time Shiro yells, which makes the woman have feelings for her father-in-law, her love for her father.
BUT my father-in-law, who is in his 70s, doesn't think so, Tadashi always thinks his son's wife likes him, he always seduces his loser for almost half his life whenever he has the opportunity (when his son goes to work)
Partly because his husband doesn't have sex often, he is very uncomfortable every time he has sex, Another part also wants to repay the cover every time her husband gets angry, the daughter-in-law is not afraid to help her father-in-law happy. And it seems, now she doesn't care about her husband's name or scolding anymore, all her affection and lust have been devoted to the older man who has cared about helping her for a long time...