Most recently, Harry and Meghan decided to leave the joint charity foundation they ran with William and Kate.
A royal expert told the Sun Online that Harry and Meghan "won't slot in line" or be "controlled" by William.
Royal commentator Duncan Larcombe said the split demonstrates that Meghan, 37, and Prince Harry, 34, intend to "do things their own way".
"It is clear that Meghan and Harry were initially prepared to slot in under the wing of William and Kate but that's not how they feel a year on."
The split from William and Kate could be a colossal blow for the Royal Foundation, which Meghan only joined after her wedding in May 2018, The Sun reported.
"Harry is going to forge his own path with Meghan. For years, before he met Meghan, he was the royal, third wheel, standing behind William and Kate," Larcombe added.
A palace insider told the Sunday Times, "William's quite controlling, and he was in control when it was just the three of them, but now he's not".