SHE’s the widow of the most reviled man in American history.

And today, Marina Oswald still struggles to rebuild her life. The former wife of Lee Harvey Oswald, now Marina Porter, lives in a rural Texas town, just 20 miles from where her husband shot JFK, forever crushing the country’s dreams of a new “Camelot.”

As the 50th anniversary of JFK’s bloody slaying in Dallas approached, The ENQUIRER launched an in-depth investigation and opened a window into Marina’s secret life – obtaining never-before-revealed information from her neighbors and others close to the Russian-born mother of three. They paint a dramatic picture of a 72-year-old grandmother torn by contradictions.

Although Marina became a proud American citizen in 1989, she still staunchly defends Oswald – insisting he never fired a shot at JFK and was set up as a patsy to take the fall for the CIA and the Mafia. She refuses to discuss the heart-wrenching events of Nov. 22, 1963, and has even posted warning signs on her driveway, advising the curious to “KEEP OUT.”

But despite the infamy she brings to her adopted hometown of Rockwall, Texas, she has been embraced by her neighbors and has settled into the life of a retired housewife, making ends meet on Social Security.

“She has endured the hatred of the entire country for 50 years and feels that she has never deserved her suffering,” revealed a close source.

Just 18 months after JFK’s mur­der, Marina married twice-divorced electronics technician Kenneth Porter, now 75, and they moved to Rockwall in the mid-1970s. By all accounts, she was a devoted mom to her two daughters by Oswald – June (now 51) and Rachel (now 50), who told The ENQUIRER: “Yes,” when asked if she believes her father was innocent.

Marina and Porter have a son, Mark, now 47.

To help her fit into the neighbor­hood, Marina worked on improving her broken English. But an incident involving Mark nearly destroyed her efforts to belong.

“Mark came over one day to play with my grandchildren – and he was carrying a rifle,” recalled 83-year-old Shirley Martin. “It frightened me in view of what had happened in Dallas. I couldn’t believe Marina let him have a gun, and I let her know I didn’t ap­preciate it. She didn’t think there was anything wrong with it, but I never saw Mark with the gun again.”

In a kindly gesture to help Ma­rina make friends, Shirley invited her and a few neighbors for tea. “One of the women was very heavy and very conscious of her weight,” Shirley remembered. “Yet Marina, who was very skinny, sudden­ly brought up the subject of obesity. I could have strangled her.”

But the years have mellowed Ma­rina, say friends. “She and Ken are good people, the best neighbors you could ever have,” said Fred McCur­ley, a frequent host of neighborhood barbecues.

Marina’s place in the neighborhood was cemented in 2011 when she joined other residents to fight a sex club that opened in a big, rented house.

“Marina was as horrified as the rest of us when the swingers moved in,” said Sherry Ann Clark.

Intense community pressure from Marina and others finally forced the sleazy club to close, and Marina and her fellow protesters celebrated their victory with a neighborhood party.

Despite striving to become a typi­cal American, the Russian-born mom has never forgotten her roots, sources told The ENQUIRER. She has made several trips to her hometown in western Russia, always taking a suitcase full of new shoes for her relatives.

Insiders say Marina’s health is good, but like many Russians, she is a heavy smoker, and in The ENQUIRER’s photo – recently taken while she was shopping in Rockwall – she can be seen dangling an electronic cigarette.

It’s not easy for Marina to get around since she’s never learned to drive. And it is not easy to contact her – she shuns Facebook and Twitter.

Sources say she has never visited Oswald’s grave. Yet she has changed her mind about his guilt. She told the Warren Commission investigating the as­sassination that she believed he was guilty of shooting the president. Oswald, she knew, had his $21.40 catalogue-bought Mannlicher- Carcano rifle with him on the day JFK was shot. He’d also left his wedding ring and all his cash behind. But after reading books on the subject and viewing documentaries, she now insists that the polite young man she met at a dance in the Soviet Union could not have opened fire on the presi­dent.

“She has done a complete 360 since she testified to the Warren Commission,” said Gary Mack, curator of a Dallas museum that memorializes JFK.

Marina’s close friend, documen­tary filmmaker Keya Morgan, divulged: “She certainly doesn’t believe the official story – she al­ways told me Lee Harvey Oswald loved President Kennedy. Marina says she remembers the day the Kennedys’ premature baby Patrick died (Aug. 7, 1963), and she found Lee sobbing.”

According to Morgan, Marina asked him what was wrong and he said: “Didn’t you hear? President Kennedy’s son died!”

Marina and Oswald, a former Marine who had defected to the Soviet Union and returned to the U.S. in June 1962, were living apart at the time of the assassination. The night before Kennedy was gunned down, Oswald was visit­ing her. He left his wedding ring – with a Soviet hammer and sickle engraved inside – plus $187 on a table by her bed. He had the rifle with him, and put it in the garage. Marina noticed it was gone the next day. The plain gold band was recently recovered by Marina, who put it up for auction in Boston. It sold to an anonymous Texas bidder on Oct. 24 for a staggering $108,000!

A five-page handwritten letter from Marina accom­panied the memento. In it, she confides: “At this time of my life, I don’t wish to have Lee’s ring in my possession because symbolically I want to let go of my past that is connected with Nov. 22, 1963.”