The U,S,A is the only country in the western world with restrictions to marrying 1st cousins, although 26 states allow it. The children of first-cousin marriages have an increased risk of genetic disorders. Apparently 10% of all marriages world wide are 1st cousins but it is predominantly in the middle east. Charles Darwin and his wife Emma were 1st cousins

Others : Johann Sebastien Bach, Werner von Braun, Albert Einstein, Rudy Giuliani, Jessie James, Mary and Joseph, Aemilia Lanyer, Jerry Lee Lewis, Sir John A. MacDonald, Prophet Muhammad, Edgar Allen Poe, Christopher Robin, Franklin D. Roosevelt, Greta Scacchi, Queen Victoria, H.G. Wells all married cousins

I would say that your case though must be pretty unique, possibly frowned upon by a lot of people, this is what I wanted from my tree sheep rustlers, armed robbers, murderers something colourful [but far enough back not to be embarrassing] to talk about in these dreary days mine were all potters or miners nearly all from staffordshire as far back as the 1700 really boring lot. Any way glad you posted your comment interesting situation good luck with your research. Just a thought I wonder what the relationship terminology will be for each families offspring's to each others???