I don't think we should look at pejoratively this practice of incest. The Greek Goddess Hera is the spouse of Zeus and his sister.
It became abhorrent with the Romans, - when the king led a licentious life having sex-relation with anybody and everybody - the brother's wife ,son's wife etc..
However marrying your mother's younger brother (your maternal uncle ) is very much prevalent in Tamil nadu , S. India even today. In fact it is considered as a blessed relation.
Partly this comes with the idea of mainting the purity of the blood-line and partly to keep the family problems of wealth and property within the family.
This problem of sex and incest , - though we have gone to moon, are preparing to go to Mars, our nature remains animal. You scratch below the skin of a man and you find there a barbarian !
Can you imagine, in today's times, a father has imprisoned his own daughter in Austria for 24 yrs. He begets 7children from her and yet pretends and tells all types of tall stories.
i suppose the same existed evrywhere in England included.
In Karela, women were not allowed to wear upper garment as per law !