According to biographer Andrew Morton, Kate Middleton and Prince William haven't always had the best of relationships.
In his 2011 book William and Catherine Mr Morton revealed how Kate struggled during the early days of her romance with the future King.
"Obstinate and strong-willed, William could be an overwhelming presence and, at times, Kate felt taken for granted - treated like a servant rather than his girlfriend."
A close university friend of the pair apparently told Mr Morton: "He (William) could flip and curt her. She didn't like it when he ignored her and got into conversation with someone as though she wasn't there.
The pal continued: "He expected Kate to run after him and the longer they knew each other the more he seemed to keep her on a tight leash."
Meanwhile, another friend told Mr Morton: "It was an edgy relationship. They were always in an out."
The book continued: "There were often spats, rows and break-ups and William and Kate tried to find their way both as young adults and as a couple," Mr Morton writes.
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