For many years, the Duke of Sussex enjoyed a very warm relationship with his sister-in-law, the Princess of Wales - even going so far as to describe her as "the sister I've never had and always wanted" in his memoir, Spare. While the pair have grown apart in recent years since the Sussexes very public split from the Royal Family, a leading royal expert has pointed out how Harry in particular will feel about losing his bond with Kate, while also making it clear where his priorities now lie.