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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