A MILLIONAIRE has been handed a £250,000 payout by his ex-wife after finding out she betrayed him for almost two decades while he believed he was the father of her three sons.

Richard Mason learned Kate Mason had lied about the paternity when doctors told him he had been infertile since birth in 2016.

Kate Mason only confessed to the illicit relationship in 2016 when Richard Mason confronted her, ten years after they divorced Credit: Richard Stanton

He made the astounding discovery when he was diagnosed with cystic fibrosis, and told he couldn't father children naturally.

Legal documents seen by the Mail on Sunday reveal Mrs Mason declared a sudden interest in Judaism when she first fell pregnant.

She also insisted all three children have Jewish middle names, something Mr Mason now believes is a clue to the identity of the real father.

Mrs Mason initially said "of course the boys are yours, no matter what the science might suggest" when he revealed he knew he couldn't have conceived them, but later confessed to the betrayal when confronted by her eldest son.

Mr Mason, from Rhos, North Wales, told The Mail on Sunday: “You don’t know what’s real and what isn’t — it’s as if I’m living in The Matrix.

“Someone says to you, ‘All you know and everything you thought solid and true is not real, and never did exist. You are not a father, you are not able to have kids, your name will not continue’.

“I still see what the boys are doing on Facebook and it’s heart-wrenching. It’s all been taken away from me.”

Richard Mason was diagnosed with cystic fibrosis two years ago and told he cannot have children Credit: Huw Evans

Richard said he was stunned to find out the boys he brought up weren't his Credit: Huw Evans Picture Agency

Richard pictured with his former partner Jen Rose Credit: Huw Evans Picture Agency

She admitted she had been seeing a man in an on-off affair during the 20-year marriage - but wouldn't name him.

The 55-year-old wealthy co-founder of internet comparison site MoneySupermarket.com had DNA tests and was heartbroken to find the 19-year-old twins were not his sons.

Their brother, 23, did not provide a sample for a test.

Mr Mason's family has been torn apart as his relationship with the boys has been destroyed by the revelation.

Due to the latest legal battle in his efforts to get back some of the enormous divorce settlement money and to sue for paternity fraud, two of his sons broke contact with him.

Richard, co-founder of moneysupermarket.com, with his new wife Emma Louise Jones Credit: Daily Post

Richard proposed to his then girlfriend Emma Louise Jones on the Venue Cymru stage in Wales Credit: Daily Post

The pair had been together for one year before he popped the question Credit: Daily Post

He believes there must have been some doubt in his ex's mind when she fell pregnant seven years into their marriage, and thinks she "tricked" him into bringing up the boys.

Mrs Mason confessed over six to 12 times she had sex with her colleague, but was adamant he couldn't be the dad as the pair always used condoms.

Two of the three have broken off all contact with the man they believed was their father for most of their lives.

His ex-wife only confessed ten years after they divorced and he had been ordered to pay a £4million settlement.

Mr Mason launched a paternity fraud case, which ended a few weeks ago when his ex agreed to pay an out of court settlement.

She decided to hand back a £250,000 portion of the lump sum after he sought to have the divorce financial settlement “set aside”.

However, the legal case allowed her to keep the biological father’s name out of proceedings.

It is not known if he is aware he is the boys’ dad.

Mrs Mason and her sons declined to comment.