Nicola Daly claimed £100,000 in council tax, housing benefit and income support payments for almost nine years.
Daly, of Tilehurst, Berkshire, was given a 16-month jail sentence for the fraud which was only discovered after her elderly mother-in-law inadvertently revealed the deception it with a residential care application.
A judge heard that Daly claimed the cash after lying to her local council that she was raising her two children alone.
In fact the cheat had lived with her partner, who worked for John Lewis, for several years and continued to do so despite repeatedly claiming she had been estranged from him for 15 years.
The trickster was finally caught after her elderly mother-in-law applied for residential care and declared that she owned a house where her son Steven Randall and Daly both lived.
The 39-year-old was sentenced to 16 months in prison at Reading Crown Court after admitting five charges of fraud and making false statements.
The court heard she is repaying the amount at a rate of £50 a month, which will take a staggering 178 years for the total to be recovered.
Alison Ginn prosecuting, said: 'Between June 2004 and March 2013, very nearly nine years, Daly claimed and received benefits in the form of income support, housing support and council tax benefits to which she was not entitled. The total amount she received was £107,154.50. She was representing that she was a single parent living with her children when in fact she lived with their father, Steven Randall, who was employed from June 2004 at John Lewis in Bracknell, Berkshire.'
The court heard that Daly had clearly stated on benefit claim forms to Reading Borough Council that she only lived with her two children, now aged five and 11 years.
Mrs Ginn said: 'Reading Borough Council requested more information and she said that she was not in contact with Steven Randall and he had not paid any maintenance for his children.' She added in subsequent claims that she had not spoken the man she lived with for 15 years.
'It all came to light when Mr Randall's mother, Ivy, completed an application for people seeking residential care, on which she said she jointly owned a premises with her son, who lived there with his partner and children,' said Mrs Ginn. 'Mr Randall's wages were being paid into this defendant's bank account, the same one into which her benefits were paid.'
When Daly was questioned by police in March 2013, she lied and said the father of her children was Mr Randall's brother Darren. She claimed to have never been in a relationship with Mr Randall and said his wages were only paid into her account as he had debt problems. However, she requested a second interview a month later and admitted her web of lies, telling police she lied as she 'thought she could get away with it'.
Graham Bennett, mitigating, said Daly had some previous convictions but none for over a decade. He said that at the time of the initial false claim, she and her partner had struggled with drug addictions and she had just given birth to their first child.
'She was in significant financial difficulties,' said Mr Bennett. 'The income support gave rise to council tax and housing benefit and the same false declarations were made. Regrettably she did not correct matters and this continued throughout the years.'
He said the couple had married in April this year and Daly was working part-time to repay her debt at £50 per month. 'It is not a repayment that is going to be dealt with swiftly but her intent is to repay as much as possible,' said Mr Bennett.
He asked Judge Johannah Cutts to consider a suspended prison sentence due to the difficulty a custodial term would present to her young family.
Judge Cutts said she recognised that 'life had been difficult' for Daly in 2004 and commended her for beating her drug addiction, but condemned her lies:
Social security support is not to pay people who feel hard up, it doesn't come from a limitless supply of cash. Taxpayers' money is used in a benevolent society to help those truly in need and you did not fall into that category.Sentencing Daly to 16 months in prIson, she added: 'It is often the families of those who commit crimes who suffer the most.'
Three related charges, which Daly denied, were left to lay on file by the Crown Prosecution Service.