Why is divorce such a taboo in the British Royal Family? Why was King Edward VIII pushed to abdicate when marrying a two time divorcee Wallis Simpson, because of the Church of England. Wasn't the Church made because King Henry wanted to divorce his wives?

One of the essential references for the abdication crisis is the diary of Henry "Chips" Channon. Gossip and snob he may have been, but he was at the heart of the matter both socially -- he was on good terms with both David Windsor and Wallis Simpson -- and politically -- he was Rab Butler's PPS and a supporter of Chamberlain in Parliament. His diaries were heavily expurgated at the request of amongst others the Queen Mother but are currently (this month! my copy is on its way from Amazon!) being published in full.

I think a pretty basic summary is that in 1935 it was unthinkable that the head of the Church of England be tainted by divorce, and even had it been possible to convince the British parliament and people (Channon thinks it would have been, and cites Duff Cooper as being in agreement, but Channon was hugely supportive of Wallis Simpson) it would not have been acceptable in the Dominions.

By the 1950s the same held, roughly, for Margaret; although by then only third in line to the throne she would have been the most likely regent in the event of her sister's death, a regency that would have lasted until about 1969. Hence no Peter Townsend.

Later, when she herself divorced in the 1970s, she was fifth in line to the throne and both Charles and Anne were of age: at that point the next in line to the throne after would have Andrew (!) who was not of age, but Ann would have served as regent. Hence, no problem with her divorcing.

By 2005 no-one cared that even if Diana Windsor was dead Andrew Parker-Bowles ("greater love hath no man than this, that he lays down his wife for his country") was very much alive, and fanciful ideas about the effect of Charles' marital status on the Dominions were laughable. Society had moved on.

There's a lot of post hoc reasons to think David Windsor was a bad man, that Wallis Simpson was little better and that their marriage was never going to result in a happy reign, but how much of impacts on the abdication at the time is hard to tell. Were there signs of his Nazi sympathies in 1935? Possibly, although how widely known they were is rather harder to tell. And in the climate of the time (appeasement) was it necessarily a problem? Was the bisexuality that Channon writes about -- Channon would know, having left his wife for a man -- known within government? Unlikely, because apart from Channon no-one else writes about it in terms. Was all the talk of Wallis Simpson having had an affair with Ribbentrop an issue? Again, not obviously. It does look like the main reason for David Windsor not being acceptable as a monarch was straightforwardly down his desire to marry a divorcee.