What is the basic plot of the story about Kunicki?

Kunicki is a character within several vignettes. He is married and has a small son. When the family takes a vacation to an island, Kunicki's wife and small son go missing for three full days. Kunicki searches everywhere for them, only to be told by the locals again and again that it is not a very big island. In later vignettes, the matter starts to degrade the couple's relationship until finally they split up.