Five years? OUCH. She neatly describes how the psychology of this situation might work for a woman.
I like how she seems so cool with the whole thing, too. I have written quite a few on that 'ho hum, I am cuckolding you, the mail is on the fridge' type of theme.
Yes. The woman being so casual makes the man realize how helpless and unimportant he is. She just isn't concerned with his upset, except perhaps as entertainment.