The Queen’s grandson, Peter Phillips, and his wife Autumn have described their separation as sad but amicable, and “the best course of action for their two children and ongoing friendship”.
The couple are in the process of divorcing, and will share custody of their two daughters.
A spokesman for the pair, who wed at St George’s Chapel in Windsor Castle in 2008, said the decision was taken after many months of discussion, and they informed the Queen and their families last year.
Canadian-born Autumn will not return to her home country, but will remain in Gloucestershire where they will co-parent nine-year-old Savannah and seven-year-old Isla.
The spokesman said: “They had reached the conclusion that this was the best course of action for their two children and ongoing friendship.
“The decision to divorce and share custody came about after many months of discussions and, although sad, is an amicable one.
“The couple’s first priority will remain the continued well-being and upbringing of their wonderful daughters, Savannah and Isla.
“Both families were naturally sad at the announcement, but fully supportive of Peter and Autumn in the joint decision to co-parent their children.
“Both Peter and Autumn have remained in Gloucestershire to bring up their two children where they have been settled for a number of years.”
The couple requested “privacy and compassion” for their children while the family continues to adapt to the changes.
The Princess Royal’s son Mr Phillips, 42, is the first of the Queen and Duke of Edinburgh’s grandchildren to divorce.
In her annus horribilis of 1992, the Queen saw the marriages of three of her four children break down, with Anne divorcing Captain Mark Phillips, and the Duke and Duchess of York and the Prince and Princess of Wales separating.
The Phillips’ split, revealed by the Sun newspaper, comes amid turbulent times for the monarch and the royal family at the start of a new decade.
Peter’s cousin, the Duke of Sussex, and Harry’s wife, the Duchess of Sussex, delivered a bombshell statement in January 2020, saying they were stepping down as senior royals and wanted to earn their own money.
In the end, after the Queen held a crisis summit at Sandringham, it was decided that Harry and Meghan would quit royal life completely in favour of a new life of personal and financial freedom, drop their HRH styles and spend most of their time in Canada.
In November, the Duke of York stepped down from royal public duties following his disastrous Newsnight interview about his association with American convicted sex offender Jeffrey Epstein.
One of Epstein’s alleged victims, Virginia Giuffre, claims Andrew slept with her on three separate occasions, including when she was 17 – still a minor under US law.
The duke, who vehemently denies the allegations, is facing calls to talk to US prosecutors and the FBI.
Mr Phillips first met Autumn Kelly at the 2003 Montreal Grand Prix, when he was working for Formula One racing team BMW Williams and she was employed in the main BMW hospitality suite.
He invited her to a post-race party and they kept in touch when he returned to England.
But the Queen’s grandson did not tell Ms Kelly he was a member of the royal family at first.
She found out after spotting him in a TV programme about the Duke of Cambridge, and confessed to being scared at the prospect of dating a Windsor.
Mr Phillips proposed during a rain shower as they walked their dog.
The bride, who was brought up a Catholic, converted to the Church of England faith ahead of their wedding.
Three hundred guests attended the nuptials in May 2008, which were kept private, but the couple posed for photographs on the West Steps afterwards with the royal family.
The celebration attracted controversy when it emerged Peter and Autumn had secured a £500,000 deal with Hello! magazine for exclusive access and pictures.
The bride wore a gown by Sassi Holford and a tiara borrowed from her new mother-in-law, the Princess Royal.
During the ceremony, Princess Eugenie read Shakespeare’s sonnet 116, conveying that love “looks on tempests and is never shaken”.
The newlyweds left in the open top horse-drawn Balmoral Sociable carriage for a reception and dance at Frogmore House.
Born in the Queen’s silver jubilee year of 1977, Mr Phillips is the older brother of champion equestrian Zara Tindall, and was the first of the Queen’s grandchildren to wed.
Peter and Zara were not entitled to be HRHs, as they are descended down the female line as the offspring of the daughter of a sovereign.
Mr Phillips runs the UK arm of events and sponsorship agency Sports and Entertainment Ltd (SEL), after a previous career working for RBS and in Hong Kong on a Williams Formula One sponsorship deal.
Questions were raised in 2016 when his agency staged the Patron’s Lunch street party for the Queen’s 90th birthday.
It was Mr Phillips’s idea, but the event was not put out to tender.
SEL Ltd was paid £750,000 for organising the celebration, but the Patron’s Fund charity defended the payment, saying there were running costs and Mr Phillips’s company had made no profit.
Mr Phillips, who does not carry out royal duties, recently appeared in an advert for milk in China.