According to reports the late pop stars' singer sis;Janet Jackson is preparing to divorce her billionaire husband Wissam Al Mana after just one year of marriage. The National Enquirer reveals: "Janet is ready to throw in the towel," disclosed an insider. "She's realized she made a colossal mistake in marrying Wissam. Janet gave up her career to be a dutiful wife - and she even took up Islam for him." But Wissam,39, who comes for the Middle Eastern State of Qatar, hasn't made any sacrifices for his 47-year-old wife, according to the insider, who adds: "He travels constantly for work, and Janet wonders if he's been tempted to stray." "She's confided to a few close friends and (her mother) that she's preparing to leave him. And she's been calling friends at all hours, crying and saying how miserable she is." As the Enquirer reported Wissam had demanded Janet sign a prenup. She wanted a guaranteed $500 million if the marriage failed before two years, but Wissam held out and said he wouldn't pay her a dime unless it lasted at least five years. Now sources say Janet is getting set to challenge the prenup and demand a fat lump sum payout from his fortune. "Her argument is that she gave up millions in earnings for her husband," explained the insider. "Janet isn't going to give Wissam a dime of her hard-earned cash. However, she's going to fight tooth and nail for a chunk of his!"