I don't know if he wanted out that early. he was reasonalbly good in WWI, tried to get to the Front, and in the 1920s he worked fairly hard at the royal tours.. but he grew bored I think, got fed up with his father and the expectations of "duty duty" all the time. I guess also he knew they would like him to marry a nice well bred girl and produce heirs and he wanted to stay with his devoted Freda.. and his other flings.Yes, Osipi, I think you are quite right. David had all the stubbornness of a weak and vain man. He was not a leader and it's always been my belief he never wanted to be King and was looking for an 'out' as early as the First World War.
But the catalyst was Wallis. If he hadn't met her, I think he would have stayed as King...