What is the significance of denver's retreating so often to the secret field behind the house?

The significance of retreating so often to the secret field behind the house is that Denver feels that Beloved's interested gaze sends her to a place "beyond appetite" and that looking at Beloved is "food enough." Beloved provides emotional sustenance for Denver in a way that Sethe never could, because Denver is simultaneously responsible for and dependent upon Beloved. Beloved's constant neediness is most like an infant's desire for its mother; when Sethe is not there for Beloved, Denver becomes a sort of surrogate mother figure. She is forced out of her role as a daughter and into a more adult role that involves working in the interest of another's welfare. The language used to describe Denver's relationship with Beloved is loaded with the vocabulary of need and desire.