Agafya is one of the Chekhov’s short stories telling about search for happiness and endurance of miserable life, also Chekhov points to the choice people make and how they later have to face the consequences of this choice.
Savka being a rather lazy and unorientated person in life is an object of passion and even love of many women in the district. He is neither contented nor unhappy about this, he just does not care. He continues to satisfy women, as they supply him with food and clothes, and other necessary things, but he feels nothing but condemn to them, no feelings, and no emotions. Savka is a kind of a blockhead, who has nothing sacred and important, but a harmless one.
Agafya is one of these women who come to Savka for a piece of happiness. She is married, and we know nothing of this marriage, but can conclude that it is not happy one. A woman happy in marriage would never cheat on her husband. This shows all the sadness of Russian society of that time, when it was not happiness looked for in the sacred bound of two souls.
The theme of infidelity is displayed in the story, but the author shows neither blame nor disapproval of it, he just states the fact of it. He leaves all he consideration to the reader, as every person has his own opinion on happiness and meaning of marriage. But when reproaching Agafya for her unfaithfulness and Savka for the lack of moral virtues one should keep in mind the circumstances of the life at that time.
Chekhov being humanist in his works, and showing love and respect for people describes them just the way they are. No characteristics, no explanation or preceding events that led to that or this deed. All can be said is that everything would have been great, if it had not been so sad.