A court was told that there was a culture of secrecy in Nigella Lawson and Charles Saatchi's marriage.
It emerged in a case involving their personal assistants, who are accused of fraud, where they spent more than 685,000 pounds on the couple's credit cards.
The 70-year old advertising tycoon had earlier accused the 49-year old TV chef of allowing their staff to spend to cover her use of drugs, the BBC reported.
Anthony Metzer, representing the Italian sisters, told the court that Lawson had lied to her ex-husband about her drug use and about the expenditure that was incurred by the personal assistants.
He said that she did so because she was fearful of his reaction, if he knew about the extent of the expenditure and drug use.
He added that if Saatchi was telling the truth then Lawson was a habitual criminal.