Prince Harry and Prince William's Separate Lives: 'It Was Only Going to Work Until They Married'

Prince William and Prince Harry are heading down different paths.

Despite the royal brothers’ very different roles — William, 36, is preparing to be the future king while Harry, 34, prepares for first-time fatherhood — longtime palace staffers had the “homogeneous idea” of the two princes working in tandem. However, it’s now clear that with the additions of Kate Middleton and Meghan Markle — and their growing families — a united foursome wasn’t feasible.

“It was only going to work until they married — and it went on a while longer than perhaps was originally thought,” one palace courtier tells PEOPLE in this week’s issue.

For more on Prince William and Prince Harry’s separate lives, check out this week’s issue of PEOPLE, on newsstands Friday

Last month, Meghan and Harry officially split from Kate and William, breaking up their joint “court” at Kensington Palace by creating two separate offices.

The Duke and Duchess of Sussex have since moved out of London to Windsor Castle’s Frogmore Cottage – about 25 miles away – and launched their own Instagram page.

“It’s a shame,” says a royal household source. “There was power in that unity and great strength in the foursome, but I see why it is happening. There is always that tension: trying to do the PR thing and then realizing that they are just real people. They want their own place and their own things.”

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The royal brothers heavily relied on each other growing up, especially in the wake of their mother Princess Diana’s death in 1997. And those who know the brothers say that the current distance between them will not last.

“There is never any doubt that they will be there for each other 100 percent and support each other when it matters,” according to one insider.

“Maybe they’ll come back together a little later,” says the source close to the royal household. “It’s another stage in the growing up. Sometimes you have to break away in order to come back.”