In "Interlunar," Margaret Atwood explores the theme of personal sacrifice and the painful realization of one's identity within a relationship. The narrator acknowledges the emotional toll of their failure, expressing a deep awareness of how it affects the other person involved. This moment of vulnerability leads to an acceptance of their limitations and the difficult choice to withdraw.

The imagery of folding "like a grey moth" symbolizes fragility and surrender, suggesting that sometimes, one must step back for the sake of both individuals. The realization that they are merely an echo highlights the struggle for individuality in the shadow of the other, emphasizing the complexities of love and self-identity in intertwined lives.