Nobody's Business

This short story left me confused as to what meaning I was suppose to take from it. In the previous stories there has either been a prominent theme or a couple of different clear messages. This story left me a bit perplexed as to what I should have learned from it. I couldn't really associate my life with this story as much as the other ones. I didn't have a connection to the characters or the situations they were going through. I felt like the only message I got was to make sure you know who you're falling in love with because they might end up really being an awful person who has affairs with other people. That seems like a pretty common sense move though. Anyways, I can't find a meaning in this- and I know there has to be one. What was the significance of Sang abruptly moving to England at the end? Why was Paul's exam repeatedly mentioned? It seemed like that didn't effect the story, but it was brought up on a lot of occasions. What was the significance of the dog at the end? I don't know if I just didn't read this story as close as I should have or maybe I just don't understand the message Lahiri was trying to present in this story.