In her new book, Unbreakable, Sharon recalls how the night before the couple's 30th wedding anniversary, she found out that her husband, who had been sober for seven years, had fallen back into his old habit of drinking and taking drugs.
"I would never have imagined our anniversary would be the beginning of one of the worst periods in our turbulent marriage," writes Sharon.
"I'd like to tell you he got me a vast bouquet of flowers and took me for a candlelit supper. But I'm married to Ozzy Osbourne."
At the time, Sharon was waiting for Ozzy to fly out and meet her in New York where she was filming America's Got Talent. The X Factor judge went through her husband's phone and was distraught when she found texts from drug dealers.
"There were texts going back months, asking people for drugs and saying 'Don't tell the old girl,'" said Sharon. "It was all there. Everything I knew I'd find but desperately hoped I wouldn't. My husband was abusing again."
Sharon discovered that Ozzy had been drinking anything he could get his hands on and had been prescribed pills from doctors all over the world, from Denmark to Germany.
"Something snapped," said the X Factor judge. "I thought, 'I can't carry this anymore'. It's what I have always done and I'm tired. I said, 'I want a divorce.'"
At one particularly trying point, Sharon said that she received a call from Ozzy saying that he wanted to be a bachelor.
"What? A bachelor? Have you heard yourself?" came Sharon's reply. "You're a pensioner. You need a bus pass, that's what you need."
The married couple of 31 years worked through their problems from last year, with Ozzy agreeing to go to alcoholics anonymous and the pair attending therapy.
Sharon moved back into the family home in June, and was said to be pleased with her husband's progress.