The relationship between Sarah and Bendrix can be viewed through either a lens of lust or a lens of love, depending on how the reader perceives their affair. Bendrix is not Sarah's first lover since her marriage to Henry Miles, so that information functions as evidence of her tendency towards lust, but as the connection between Bendrix and Sarah develops and eventually ends, their attraction begins to look more and more like love.
Lust is a matter of physical attraction, while love depends on emotional attachment. Sarah's intense guilt over her cheating on Henry as well as her inability to leave the marriage for Bendrix despite her unhappiness suggests her emotional life is a deep one. Her tendency towards strong and enduring emotions may indicate that Bendrix has more of an emotional hold on her than a mere physical one. As well, Bendrix's obsessive thoughts about Sarah and his borderline hatefulness towards her prove the depth of his feelings; hate is the flip side of love, after all. As well, Bendrix experiences great confusion and heartache when Sarah breaks off the affair, also proving that he feels something much stronger than mere lust for her.