I would like to clarify one thing about the times that this song was written in. It was socially acceptable for both males and females of the time to take lovers on the side. At the time it had the signifigance of belching in public. In poor taste, but hardly a crime.

It seems to me that this is a tragedy of estimations. Lady Arlen underestimated what Arlen felt for her. Matty underestimated what Arlens reaction would be (that is why he risked staying. The Servant underestimated the consequences of letting Arlen know what was going on. Arlen overestimated his wife's love for him. And the only person who had any idea what was going to go down was the hornblower who was riding with Arlen because he was able to see its affect on Arlen.