What is the theme in The Lotus Eaters: A Novel by Tatjana Soli?

Relationships are at the core of the story. One of the most important relationships is between Helen and Linh. At first they started out as colleagues but then became lovers. By the end of the story, when Saigon falls, Linh and Helen see themselves as a married couple and even present themselves as such when trying to get out of the country.