"The eldest was a son, who gave up the thrown to marry an american divorced woman. The throne was then given to Elizabeth because the Queen Mum was not a blood family member."
You're mistaken, my Lord Corporate Recreation. You wrote a partially true story. Indeed, His Majesty then chose to abdicate the thrown than give up the divorcee love of his life. Nonetheless, it was not Her Majesty Queen Elizabeth who inherited the thrown immediately. It was her father who was the brother of the resigned King who inherited the throne. I believe Her Majesty's (Queen Elizabeth, that is) father was just a duke right before his brother abdicated the throne. And then when her uncle abdicated the throne, her father took over. When he died, then she automatically inherited the crown/throne for the reason you mentioned (i.e., the then Princess' mum (now Queen Elizabeth) was was not a blood family member).
Anyone can correct me if I'm mistaken somewhere. 🙂