The novel Atonement by Ian McEwan is full of emotional richness and complicated human interactions. Many poems share a common theme with this novel, but here are a few for your consideration.
Both Atonement and Shakespeare's "Sonnet 29" address themes of dissatisfaction with one's own lot in life and the thought of a beloved individual as providing relief of that unhappiness. At times throughout the novel, which takes place before and during World War II, unhappiness dominates the various atmospheres of the book, and happy memories of a loved one provide some respite for some characters.
Because the main conflict of the novel relies on the relationship between two sisters, Ann Taylor's "About The Little Girl That Beat Her Sister" could make for an interesting read. The poem addresses the bad treatment of one sister towards another, which echoes the challenges faced by both Briony and Cecilia.
Finally, poems about World War II generally relate thematically to Atonement. Some classic poems of this time period include "The Death of the Ball Turret Gunner" by Randall Jarrell and "This Day This World" by Stanley Kunitz. Other poets to consider who wrote about World War II are Karl Shapiro, William Meredith, and E.E. Cummings.