Originally Posted by DJ Happy

I'll have a dab at explaining:

The blood monarch (i.e. the individual from the Windsor blood-line) must enjoy an elevated status over everyone else in the House but can still only be awarded a title in matching with their gender. Therefore, if the blood monarch is a woman ((like the current Queen Elizabeth II), then she can only be called a Queen and must be the highest ranking individual in the house. The person she marries cannot be called the King as he would then rank above her. As such, he is awarded the title of Prince Consort, ranking him above other princes but below the Queen.

If the blood monarch is a man, however, he will be the King and his wife will be the Queen.

In the case of Prince Charles and Horse-Face, the objection to her becoming Queen is not a legal one but more of a moral one. Because of the affection the public has for the late Lady Diana, it was decided that Camilla should not become Queen once Charles succeeds his mummy.

In the case of Edward the VIII's abdication, that was necessary as he was marrying a divorcee, unnacceptable for someone who would become head of the Church of England. Although it appears to be perfectly acceptable for the head of the Church of England to be a divorcee himself, thanks in part to Henry VIII.