I am just starting the book as I had to wait for the library copy so I won't comment yet on overarching themes.
I am really enjoying reading the book not so much as a story of love, obsession or sex but as a novel that shows a time and place I do not know much about otherwise and a novel with many wonderful little details. My two favorites so far are the old woman who decides to return to the whorehouse of her youth to live out her old age and the line about not worrying about the civil war in the cities because they kill you with decrees not bullets.
In response to fantasy fans comment about Ariza stalking a teenage girl, I think that in that time and place girls were expected to marry earlier and were an appropriate object of romantic interest.
On a more frivolous note, "The Book Group", a British TV show streaming on Netflix has a n episode entitled magical realism in which this book is the club's selection of the month. It was fun to watch that episode while starting the book myself.