A Good Marriage (2014)

Shortly after celebrating his 25th wedding anniversary with her husband (Anthony Lapaglia), Darcy (Joan Allen) is looking for a battery in the garage when he is away on a business trip, only to find out that his husband is the "notorious serial killer Beatty" in the news. The novel blueprint of the film is part of King's collection of short stories (Full Dark, No Stars) published in 2010. King said in an interview that the novel was inspired by Dennis Rader, an American "BTK serial killer" who was arrested in 2005. He had a wife, Paula, who had been married for 34 years and had no knowledge of his behavior. King said that what the novel is about is that people can never fully understand each other, even the ones they love the most.