The Great British Bake Off judge and Alexandra, his wife of twenty years, confirmed the break-up in a joint statement.
Sources close to the couple say the marriage has struggled to cope with Paul’s wandering eye after his fame skyrocketed – including an affair while working in the US.
And pals say the marriage has been secretly finished for some time.
An insider said: “The truth is they’ve worked really hard to salvage their relationship but just couldn’t recover from the damage that had been done.
“The more famous Paul has become, the more attention he has been getting, and that has put huge strain on the marriage.
“He’s so recognisable that it’s now got to the stage where he simply can’t go anywhere without fans, often attractive, younger women, racing to get close to him.
“Paul plays up to it and enjoys the attention which he thinks is harmless but obviously Alex doesn’t see it that way — especially after his affair.
“Sadly, this has been on the cards for some time. Now they’ve made it official.”
In their full statement yesterday the couple vowed to focus on the wellbeing of their teenage son Josh, 14 – but did not say whether any third parties had been a factor in the marriage breakdown.
The announcement read: “It is with sadness that we have decided to separate.
“Our focus continues to be the happiness of our son, and we would ask the press and public to allow us privacy as a family during this very difficult time.”
Paul, 51, and Alex, also a chef, married in 1998, but previously separated in 2013 when the TV chef admitted to having an affair with his sexy co-star on the US version of Bake Off Marcela Valladolid, then 35.
They reconciled a few months later and he described the incident as “the biggest mistake of my life” in an interview at the time.
But industry insiders revealed he had fully intended to start a new life with Marcella – until she pulled the plug on their fling.
A source added: “Paul was totally into Marcela and threw himself in with both feet.
“When it all fell apart he went back to Alex with his tail between his legs, but in reality if Marcela had wanted to keep it going he was all for it.
“He really believed he was going to start a new life with her, but in the end she walked away and he was left with nothing.
“He went back home and begged for forgiveness — but things were never the same.”
But he was last pictured at a televised charity event without his wife by his side, instead joined by former Bake Off winner Candice Brown.
The 51-year-old baker will return as a judge for the second series of Channel 4’s The Great British Bake Off next year.
Last December him and Alex spent £1.4million a five bedroom Grade II-listed mansion in Kent — located just a few miles from his previous home in Kent.
The sprawling home is set in over 10 acres of land, perfect for growing his own produce.
It also features a swimming pool and paddock, as well as a summer house, detached house and log barn.
But by July this year, Paul began taking greater control of the companies he and Alex are directors of. He became the majority shareholder of both PJH Media, and Paul Hollywood Limited — which have more than £1.1million in assets between them.
Paul is now listed as the sole “person with significant control” in official paperwork, meaning he owns 75 per cent of the company shares and has the right to remove other members.
He is the sole director of his big money-making other firm, HJP Media LLP, which he uses to channel his solo projects.
The most recent accounts show he holds assets worth as much as £8.7million.
He became the majority shareholder of both PJH Media, and Paul Hollywood Limited — which have more