This happened a lot back in the 19th century pre civil war. Our ancestors looked around at that years’ crop of cousins and the chaos of the civil war and moved west in the mid to late 19th century. Mr. Mercat is related to Mary Todd Lincoln whose parents were cousins and so on going back another two or three generations. He’s pretty sane though so I’m guessing that it all got sorted out.
i’m researching families in old cemeteries. noticed that some families have married cousins and most of the children of the next two generations died young....10’s 20’s, 30’s