X Factor 's Sharon Osbourne has revealed how she knew of Simon Cowell and Dannii Minogue's affair , claiming that the Aussie judge became 'unbearable to work with' as she grew closer to the show boss in 2007. Writing in her new autobiography 'Unbreakable', which is being serialised in The Sun , Mrs O said: "During filming it was obvious to me that there was some sort of relationship going on ...