Prince Harry's Marriage Rocked by His Flirty Messages to a British Journalist — Despite Wailing He Hates Hacks

Their messages were playful, cheeky – and undeniably flirty. Responding to an early message from Prince Harry, Charlotte Griffiths wrote: "Hello Mr Mischief ... What a fun weekend of naughtiness – can't we all get up to no good in the countryside every weekend damn it?? Smooches..."

RadarOnline.com can reveal seemingly amused by his new, mischievous nickname, Harry pushed back – "I was surely no worse than anyone else" – but Griffiths assured him it was a "compliment," adding: "We all competitively out-naughtied each other, which is why we all had so much fun."

The banter continued over the following days. Griffiths dubbed the prince a "bloody maverick" and asked about his "Thirsty Thursday" plans, while Harry shared he'd been busy and was "gonna be hungover again for the third day running." He added she'd "missed a good party," signing off with an affectionate "Mwah xxx."

A month later, after Griffiths shared details of a ski trip in Klosters, Switzerland, Harry replied, "I WISH I was there sugar but unfortunately stuck in Cornwall doing Army stuff :( Otherwise I would have been there playing and then drinking u under the table, obvi!!" before longingly adding, "Miss our movie snuggles."

The cozy, sometimes late-night exchanges – sent over Facebook between December 2011 and January 2012 – came as a shock when they were revealed in court last month, not least because of who Griffiths turned out to be: a journalist for one of the outlets Harry is now suing.

The intimate messages surfaced in the closing stretch of his privacy case against Associated Newspapers Limited, publisher of the Daily Mail and Mail on Sunday, where testimony wrapped up on March 31. Harry and fellow claimants, including Elton John and Elizabeth Hurley, alleged they are victims of unlawful information-gathering. Associated denied the claims.

According to evidence presented to London's High Court, the 41-year-old royal first met Griffiths – now 40 and an editor-at-large at the Mail on Sunday – at a country house party hosted by a mutual friend.

Now, a source told RadarOnline.com, the fallout is hitting closer to home. "This is an extremely embarrassing situation for Harry as well as [Duchess] Meghan [Markle]," his wife of nearly eight years, said the source.

A rep for the couple denies the story.

"The fact that this exchange between Harry and another woman has all been revealed in open court is a total nightmare, not just because it may weaken his case by showing he was fraternizing with the press at a time he claims they were persecuting him, but it also paints him as a flirty, hard-partying character who clearly has skeletons in his closet that Meghan doesn't or didn't know about."

The former Suits actress, 44, was "shocked to hear about this other woman and understandably wants to know the full story and the precise nature of their relationship," claimed the source.

Harry sees it differently. "He's defending himself passionately, saying this all happened a very long time ago and once again it's a case of the press and their legal pitbulls trying to sling mud at him and hope that it sticks. He acknowledges having a playful [exchange] with this woman. But he's swearing up and down that's as far as it went – just a bit of friendly fun and that there's no need to read between the lines or associate his behavior back then with who he is today."

The timing, however, couldn't be worse.

"Everyone knows Harry and Meghan have been under colossal stress recently. They're constantly putting out fires and dealing with crisis after crisis," said the source.

The revelations emerged in court as the couple is facing mounting pressure on multiple fronts. As RadarOnline.com has previously reported, the Sussexes are navigating tensions over Harry's efforts to reconcile with his cancer-stricken father, King Charles III, 77.

While Markle will always support him repairing that rift, she remains wary they'll ever find true peace with the royal family after leaving Britain six years ago. Still, as reports earlier this year suggested, Harry could soon regain government-funded security in the U.K., potentially paving the way for a return, this time with their kids, Prince Archie, 6, and Princess Lilibet, 4.

The strain isn't just personal. Their initial Netflix deal, worth a reported $60million, was downgraded to a first-look arrangement last summer, and the second season and holiday special for With Love, Meghan, underperformed in the ratings last year, with reports indicating there are no plans for another full season.

In early March, Markle and Netflix also announced they'd ended their year-long partnership in her As Ever lifestyle brand, though both sides insisted that was always the plan.

Then, a recent report from Variety cited growing frustrations behind the scenes at the streamer, suggesting the Sussexes' entertainment ambitions may have hit a wall – claims both Netflix and the couple's lawyer have denied, confirming they still have multiple projects on the way, including two book-to-film adaptations and a scripted polo drama series.

At the same time, Harry's ongoing legal battle has dragged other royals into the spotlight, and secrets have been exposed. In pre-trial submissions, his legal team alleged that Prince William, 43, and Princess Kate, 44, were also targeted by private investigators working for the Mail, including claims that confidential details about William's 21st birthday party and Kate's phone and contacts were obtained.

Behind the scenes, the emotional toll is heavy, the source claimed.

"It really irritates Harry that people are trying to stir up trouble between him and Meghan, since he maintains [these messages are] ancient and irrelevant history. But try telling that to Meghan," said the source, who claimed the duchess is "humiliated" and has been "in tears" after being "blindsided and betrayed because she never knew this was coming." According to the source, Markle has wondered: "What else is he hiding?"

Amid increasing attention – especially as the Sussexes head to Australia in mid-April for a series of private, business and philanthropic engagements that are already being heavily scrutinized – it's just one more problem the couple didn't need.

"A lot of people are now asking if this could be the straw that breaks the camel's back for Harry and Meghan," said the source.

"They were already on shaky ground – but this could well tip them over the edge."