I find disturbing how sad he was when his brother got married. It shows how insecure he is - which is understandable as he lost his mum at a young age. But dealing with your trauma it's learning that's ok, people around us will make other strong bounds, it doesn't mean they love you less.
Then he talks quite a lot about his dream to form a foursome with William, Kate and his future. The reaction of his brother is quite condescending but again it's a bit weird idea - aren't you supposed to want to lead your own life with your partner and be on your own, with your own projects? It shows either again insecurity or that he really thought he just needed to marry to be put on an equal foot with the Cambridge couple. But that was foolish to think that was a possibility. It's the nature of a monarchy to be ruled with a strict hierarchy. It seems like he have always wanted to escape the way the monarchy is functioning. It's quite delusionnal from him.
It's quite interesting to see that he's always been scared to lose people in his life - maybe that fear was so strong that it lead him to burn bridges. It's quite common people with this quite of deep insecurities decides to choose to destroy those relationships. It makes them feel in control. They think they cannot avoid rejection but at least they could choose how it would happen. This book seems to be a good exemple.
Last thing, it's quite disturbing to see that many rumors that the tabloid press was relaying were actually quite true. I always thought that it was a lot of bs to get some clickbait and antagonise the different members of the RF because it sells. But Harry shows how truly the RF is disfunctional.