I think Mr.Fitzgerald made a good choice on writing his characters in a way in which they intertwine into Dexters life. One of the big characters that have a huge impact on his life and leave a big sequence of events is Judy. In the beginning when he first meets
her, it's one of those sequeces that gets set in motion which leads to him quitting his job.
Judy continues to be a big part of his life by playing with his heart, which obiviously makes Dexter very confused. I think Fitzgerald wrote judy in a way to teach Dexter a lesson. Her fickleness also shows his views on women during his time period. Dexter's bretrayal shows what might've been in his life and what path it could've gone. Dexter's eventual downfall is his life long chase for the finer things in life. In which he realizes he's chased something that doesn't matter.