To really sell a torch song, a singer needs a torch. Frank Sinatra, master of the love ballad, found his flame in the sultry charms of Ava Gardner. For three explosive years the crooner and the actress fueled headlines, fascinated a nation and broke up the furniture with their free-for-all affair.

From the moment the 130-pound son of a Hoboken fireman spotted the 36-20-36 daughter of a North Carolina farmer on the MGM lot in the late 1940s, he was head over heels. "I'm going to marry that girl," he told a pal. She at first thought he was conceited and overpowering but soon found him irresistible. And though Frank already had a wife, Nancy, and three children, he and Ava started partying in 1948. Studio boss Louis B. Mayer railed at the 26-year-old Gardner to avoid the married Sinatra, 33. It was, after all, the age of morals clauses in contracts and puritanical public opinion. But the criticism drove her into his arms.

"They loved fun, and they loved their quiet moments," says Kathryn Grayson, an old friend and costar of the pair. At parties in her Santa Monica house, she recalls, "they sat in the corner and held hands. They had their fights too."

The scrapping, in fact, never seemed to stop. "He has a temper that bursts into flames," said Gardner, "while my temper burns inside for hours." They quarreled over politics, music and, of course, other lovers. Frank was insanely jealous of Ava's second ex-husband, bandleader Artie Shaw (Mickey Rooney was her first). When he found Shaw with her one night in 1950, Sinatra fired two shots—into his own mattress. For her part, Ava wanted Frank to get out of his unspooling 11-year marriage (Frank dragged his heels), and she once stormed out of a club when she thought Sinatra was singing to actress Marilyn Maxwell. "We were always great in bed," the salty Gardner once said. "The trouble usually started on the way to the bidet."

Sinatra finally obtained a Nevada divorce and married Gardner 72 hours later on Nov. 7, 1951. But the couple's careers were out of sync. Sinatra, who had been the nation's No. 1 singer, was having trouble filling concert halls and selling records because his bobby-soxer fans had grown up—and the self-destructive affair with Gardner only made matters worse. MGM would soon cancel his movie contract as well. Gardner, carefully groomed to become a screen goddess, was hitting her stride. In 1952, with nothing much to do, Sinatra accompanied her to the African set of Mogambo, in which she starred with Clark Gable. Frank built Ava a shower in the scorching desert and lavished gifts, including a diamond ring, on her for their first wedding anniversary. When she found out that Sinatra was broke, she said to cameraman Robert Surtees, "You know what the son-of-a-bitch did? I got the bill for the ring!"

By 1953, Sinatra was back on top. He won an Oscar for his portrayal of Maggio, the drunken soldier in From Here to Eternity. Soon he was busy with other films and back in the recording studio. "Work took him in one direction and her in another," says Grayson. "They couldn't be together enough." Ava soon began losing interest in the relationship. Their separation was announced in October 1953, although they didn't finalize their divorce until 1957.

After the split, Gardner rebounded by moving to Spain, where she took up with bullfighter Luis Miguel Dominguin. But Sinatra, suffering from insomnia and depression, drowned himself in liquor and remorse. At his L.A. apartment one night, he walked away from a card game with songwriter Sammy Cahn and others and went into his den, where he tore up a photograph of Gardner and smashed the frame. Then he began trying to put the photo back together. For many years, on sound stages and in dressing rooms, Sinatra kept a picture of Ava taped to his mirror. "They developed a great friendship," Grayson says. "They helped each other. I think they wanted to get together again, but circumstances kept them apart." Despite a lineup of bullfighters, playboys and actors, Gardner, who died in 1990 at age 67, never married again. "She told me," her friend actress Arlene Dahl told PEOPLE at the time of her death, "that she never loved another man as much as she loved Frank."