What is the theme in Great Short Works by Fyodor Dostoevsky?

Sexuality is a major theme in the book. This theme asserts itself in different ways during the stories. In some stories the main character is a young single man, who might be a bit naive. For some, the intention is to get married. In one of the stories the drama is about a few facets of human sexuality. One is the challenges involved in what is often times a change over, from same gender best friendship pairings, into the condition of being part of a couple.