Critics, such as John Bayley, tell us that Tolstoy disliked Family Happiness as soon as he completed it: "the main (reason) seems to have been because the story was made up." Tolstoy lacked experience with the events he was narrating. Tolstoy seems to be right. The story is well-written, but it does not fully explain the reaction of the husband in the tale.
The first half of the story details the developing love of a seventeen year old girl, who grew up secluded in the country, to a 36 year old business man, a friend of her father, a man more than twice her age, who had traveled much. The second half tells about her life after her marriage; both she and her husband are very much in love.
However, she discovers that she is bored with life and persuades her husband to live some months in the large city. She attends many social events there and experiences a life she only heard about, a life that her older husband had long ago experienced and no longer needed or desired. Her new life creates a rift between the couple. The husband clearly loves his wife and gives her all she desires, but the love changes. It dissolves into a love that many middle age couples experience.
She realizes her mistake and tries to reignite the former deeper happier love, but her husband, who insists that he loves her, tells her that there is no possibility to return to the first love. It is this decision by the husband or his insight that is not sufficiently explored.