Why is it so hard for men and women to live harmoniously with each other according to "The Kreutzer Sonata"?
While it may be correct that the idea of chastity in marriage is far-fetched, it is true nevertheless that many married couples end up hating each other. Tolstoy says in "The Kreutzer Sonata" that he and his wife were like two convicts held together by a chain and both hating each other because they were chained together and unable to separate because of the chain. In his day it was extremely difficult for people to get divorced. Now it is easy, and about half the marriages in America end in divorce. People get married because they are supposedly in love. But there is something about marriage that poisons love. Maybe Tolstoy was right in thinking that it is too much physical intimacy. There must be some reason for it. John Collier's humorous short story "The Chaser," much discussed in eNotes, gives a funny take on the same problem.
I just finished reading it and saw your question.
Tolstoy's beliefs come through in Pozdnyshev's narration of the crime. Pozdnyshev/(Tolstoy) believed that men and women could not find true peace unless living in chastity and abstaining from any physical relations, other than for the procreation of children If this is not done, then the jealousy of either will take precedence and there can be no true love or harmony. Each will view the other with uncontrollable passion that leads to viewing each other as objects for satisfying one's pleasure.
This idea is so far-fetched from our current times that I'm sure most will dismiss it. However, I agree with the premise, if one can find two people in today's world to attmept this feat. Hope this helps.