Prince Harry and Meghan Markle bring out the worst in each other, according to a royal biographer.
Angela Levin, author of Harry: Conversations with the Prince, claims Meghan is a "mega-watt attention grabber with the eyes of the world on her" and that Harry has "faded in her shadow", according to the Daily Mail.
She wrote in Britain's Daily Telegraph that Meghan had proved she wasn't a "team player", but instead a "fiercely ambitious woman who wants to be number one".
Levin then added that Harry had turned from "charismatic and accessible" to a "nervy, tense man who seems constantly on edge".
She said Meghan "seemingly finds it difficult to compromise" and may be someone who "zooms in on the negative" unless "everything and everyone around her" is going the way she wants.
The royal expert went on to say that Harry had been the right combination of "royal stardust" and "accessible everyman" before he met Meghan.
She added that Harry, a "warm young man", had changed as Meghan's "dark side" had "enveloped him".
Her comments come as it's been revealed the couple will never return to their official roles following the release of the biography that laid bare their rift with the royals.
It's "torpedoed" whatever chance they had of creating a new position with the help of the other royals when their trial period in the US is over, sources say.
And it's feared the book's revelations will also harm efforts to repair their relationship with William and Kate.
A royal household source said the door would always be open to them as members of the family.
"But it's hard to see how they can now salvage the new role they wanted as "hybrid" royals, running commercial careers alongside royal duties from the US."
Another source told the Daily Mail that the review period hasn't been discussed but it seemed there was "no way back" for them now.
"Some very private family matters have now been aired in public. That will be hurtful."