"The Edge of Love" is a 2008 film about nightclub singer Vera Phillips and poet Dylan Thomas who fall in love despite both of them being married. When Vera's husband, William, returns from the war with post-traumatic stress disorder, the couples must face the consequences of Vera and Dylan's affair.
The movie is set in London during World War II. Vera, played by Keira Knightley, reunites with her ex-boyfriend, Dylan played by Matthew Rhys, and the two rekindle their old feelings. However, Thomas is now married to Caitlin MacNamara, played by Sienna Miller, and has a child with her.
Vera and Caitlin become unlikely friends, and the three maintain a close friendship as they enjoy the London nightlife, but tensions mount as Caitlin notices Dylan’s jealousy over Vera marrying soldier William Killick, played by Cillian Murphy.
Shortly after William is deployed to Greece, Vera discovers she is pregnant. She gives birth to a son and moves with Caitlin and Dylan to a pair of neighboring cottages on the Welsh coast to bring up their children away from the dangers of London. The feelings between Dylan and Vera intensify, and their relationship makes Caitlin uneasy.
When an emotionally unstable William returns from the war and discovers Dylan and Vera's relationship, he lashes out violently toward both Dylan and Cailtin.