Mr Middleton has credited Catherine, 43, Pippa, 41, and mother Carole, 70, with helping him overcome a mental health crisis in 2017 that lead him to consider taking his own life.
He said that having such “strong women” around him taught him that “vulnerability wasn’t weakness, it was strength”.
His cocker spaniel, Ella, was also central in getting him through this period, which is the subject of his new memoir.
“She gave me a reason to get up, to go outside, to care, ” he explained.
Of his two sisters, Mr Middleton said they have always been “in tune with the people around them”, adding that their “emotional intelligence rubbed off on me, even if I didn’t fully realise it at the time”.
“Looking back, I think it gave me permission, in a way, to feel things more deeply and to name those feelings when they came up,” he added.
“That doesn’t mean I always found it easy. In fact, like a lot of men, I struggled with expressing how I was doing when I was at my lowest.”
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