Princess Diana was  teenager in love when she married Prince Charles, but their marriage “went sour” and a new tell-all book from a royal insider is revealing the “humiliation” she felt by his scandalous affair with Camilla Parker-Bowles and the “dark days” she suffered through as an unhappily married woman.

The late princess, who was killed in a Parisian car accident that many believe was murder, was loyally served by her press secretary Dickie Arbiter for 12 years and he has penned a poignant memoire about his time serving Diana titled “Was That Alright?”

He began working for the royals in 1998, seven years before they filed for divorce and watched as their marriage crumbled.

“She had a relationship with her husband that…went sour,” Closer magazine reported Dickie said.

An insider told the magazine that the book will reveal that “Diana was madly in love with Prince Charles at the start of their marriage.”

However, the fairy tale would soon begin falling apart with an increasingly isolated Diana.