What is the main conflict in Heartburn by Nora Ephron?

The novel's main conflict might be seen to be the dissolution of a marriage. Rachel and Mark's marital problems, however, take second place to the conflicts taking place with Rachel's character, as she attempts to come to grips with her husband's infidelity and learns that she does not have to change in order to be worthy of her husband's love..... she merely needs to come to grips with herself and understand that he is not worthy of the love she has to give.