Harold Robbins: New tell-all book by ex-wife of best-selling novelist Harold Robbins claims he demanded an 'open marriage,' had affairs all over the world and hosted wild orgies By Snejana Farberov For Grace Robbins, the ex-wife of one of the world's top best-selling authors of all time, life was a Cinderella story filled with luxury and leisure - but it also had a dark side driven by her husband's chronic infidelity. In her new book, Cinderella and the Carpetbagger: My Life as the Wife of the World's Best-Selling Author, Grace Robbins reveals how Harold Robbins demanded that they have an 'open marriage,' carried on countless affairs and even hosted group sex parties in their home. Robbins, described in a recent biography as 'the man who invented sex,' penned more than 20 novels in his lifetime, which sold about 750 million copies around the world. He has been credited with - and blamed for - launching the sex-power-glamor genre of romance novels popularized in later years by the likes of Jackie Collins and Danielle Steel. Portrait of marriage: Grace Robbins (left), the ex-wife of one of the world's top best-selling authors, Harold Robbins, wrote a tell-all book (right) about their complex relationship where love coexisted with infidelity Married bliss: Harold Robbins and Grace tied the knot in Las Vegas in 1965 and had a daughter together While most critics dismissed him as a 'speed typist' and a 'subliterate' cranking out pulpy romances rather than a respectable author, that did nothing to stop him from attaining incredible commercial success. Years after he died from respiratory heart failure in 1997 at age 81, Robbins was granted a star on the Hollywood Walk of Fame. Grace Robbins, the novelist's second wife, writes in her memoir that her husband would go on prolonged 'research' trips, during which he would openly have trysts with other women. She says in her book that while Robbins was writing his 1971 best-seller The Betsy, her husband plainly told her: 'I gotta have sexual gratification, especially when I'm away from you,' The New york Post reported. According to Grace, her philandering spouse was always brutality honest with her about his sexual encounters on the road. "These will be brief meaningless affairs," she recalls being told. Greatest hits: Robbins penned more than 20 books in his lifetime that sold 750 million copies, with two of the best known novels being The Carpetbaggers (left) and The Betsy (right) The writer, however, made it clear that if in his absence his wife was in need of male company, she was free to take on a lover as well. Upon his return from his wanderings, Grace writes that her husband would share with her tales of his sexual exploits. 'He told me several stories I didn't want to hear, very clinically, with all the sordid details, as if he were a doctor describing his latest surgeries. Harold Robbins counted among his many paramours a noblewoman from St. Tropez, France, married to an Interpol agent, and the wife of an ABC television executive whom Grace caught coming out of the shower at her husband's office. Charmed life: The Robbinses shared their time between their Southern California estate, a summer home in the south of France and their yacht, Gracara. Wild one: Robbins would go on long research trips, during which he would have affairs with women and then come home to tell his wife all about them. The writer also hosted orgies in their home At one point, Grace describes how her husband invited a former drug addict and vagrant resembling 'a drowned rat,' whom he had met on the beach, to live with them. The virile, sex-obsessed Robbins later began hosting orgies at their home, and even got his wife to take part in one encounter with two other women. "I thought, "I don't want to do this." I sprang out of bed and excused myself ever so politely,' she recalled the ordeal. Grace met Harold shortly after reading his arguably most famous book, The Carpetbaggers - a 1961 novel loosely based on the life of the enigmatic aviator and filmmaker Howard Hughes, which takes the reader on a whirlwind adventure from New York to California. Grace Robbins writes in her book that she fell in love with the novel and was determined to meet the author - a plan that came to pass with the help of a friend who had arranged a luncheon with Harold in New York, The Desert Sun reported. Philanderer: Robbins, pictured in this 1984 photo in the company of four leggy beauties, had numerous affairs around the world, counting among his lovers a French baroness and the wife of an ABC network executive In 1965, the couple got married in Las Vegas and had a daughter. The Robbinses knew how to live in style, sharing their time between their Southern California estate, a summer home in the south of France and their yacht, Gracara. The couple also became known for their wild parties featuring A-list guests like Frank Sinatra, Lana Turner, Don Rickles and George Hamilton. Looking back on her time with Robbins, Grace said their years together were the happiest in her life, but her husband's drug use and growing need of extramarital affairs put a strain on their relationship. Grace herself found comfort in marijuana and had flings of her own, including a brief tryst with Sammy Davis Jr. that began during a surprise birthday party for the famous Rat Pack member. Last love: After divorcing from Grace in the early 90s, Robbins went on to marry Jann Stapp, pictured here in 1996 - a year before his death "I'll show you mine if you show me yours," Grace recalls Davis telling her. I did not have time to answer, for suddenly he whipped it out and was indeed showing it to me. In mid-80s, the Robbinses' frivolous fairy tale came to an end when Harold suffered a serious accident that left him in need of constant medical care. He stopped cranking out books at the breakneck pace of years past, the couple were no longer hosting lavish parties, and the bills started to mount, forcing them to sell off their many houses. The couple finally called it quits in the early 90s, but Grace Robbins insists that despite their low moments, their love was real.