COULD TWO MEN'S SECRET LIVES DRIVE THEM TO MURDER THEIR SPOUSES?, ON "PRIMETIME: FAMILY SECRETS," TUESDAY, JULY 22 ON ABC

How well do people really know their spouses? This week's "Primetime: Family Secrets" reports on two stories in which seemingly perfect marriages go horribly wrong when both husbands become prime suspects in their wives' murders. From a man who is charged with shooting his wife and baby in their own bedroom to another man who is suspected of slowly poisoning his wife to death, the program examines what might drive these men to commit such heinous acts. "Primetime: Family Secrets" airs TUESDAY, JULY 22 (10:00-11:00 p.m., ET) on ABC.

British born Neil Entwistle met his American wife, Rachel, on the York University rowing team when Rachel was 19. After graduation they married, had a baby daughter and Neil persuaded Rachel to move to the outskirts of Boston, MA near her family. Many who knew the couple said that he was a loving father and husband and that they were happily married. But in January 2006, Rachel and their nine-month-old daughter, Lillian, were found dead in an execution-style shooting in their bedroom. Martin Bashir follows the case of Neil Entwistle, who is charged with the murders.

According to prosecutors, the 30-year-old computer engineer from Worksop, England was living a hidden life of lies and sexual deviance. He had told his wife he was receiving a monthly income of $10,000 from a top secret intelligence contract in the UK. In reality his life was unraveling and he had maxed out at least eight credit cards. Another disturbing side was an unknown predilection for internet sex. He took a self-portrait in the garden at his parents-in-law's house, where he was naked and aroused in a lounge chair. The pornographic image was posted on a website used for soliciting sex and was captioned, "I am looking for one on one discrete (sic) relationships with American ladies." Bashir reports on how Entwistle's alternative life could have led him to brutally murder his wife and daughter.

Then: Can one half of a couple be blissfully happy and unaware that the other is desperate and out of control? Jim Avila reports on how James Keown's money troubles and lies escalated to being charged with poisoning his wife to death. Julie Keown was studying nursing in Jefferson City, Missouri when she met her future husband. They married in 1996 and settled down in Kansas City, where James became a popular local radio personality. Life seemed good and Julie would often email friends about how happy she was. She did note, however, that money was an issue for James and that he dreamed big. In 2004 James announced he'd been accepted to Harvard Business School, despite not graduating from college, and the couple headed to Waltham, MA. But eight months after their move, Julie started to have strange physical ailments. She woke up one night with slurred speech and was incapacitated. Doctors were stumped as to the cause and a couple of weeks later she had another strange "attack" that put her into a coma. This time doctors decided to test to see whether she'd been poisoned. But it was too late for Julie. Avila reports on the disturbing and methodical plan that police suspect James used to poison his wife, lacing his wife's Gatorade with anti-freeze. Prosecutors accuse James of telling a whole series of elaborate lies and assert that ultimately money drove him to poison his wife.

David Sloan is the executive producer of "Primetime: Family Secrets."