They were born within a couple of years of each other and both were called William.
William SAYERS was born on the coast, in Filey, and followed his father to sea in a small coble, to catch fish. He did well not to drown and raised a large family with his wife Susannah. The census enumerator found the couple at home with five children in 1841, eight in 1851, and ten in 1861. William died in 1892 aged 78; Susannah the following year, aged 75.
Seventy miles to the west the other William, with the singular family name SAYER, had six children with his wife Mary, before she died at age 36 in 1851, just a few days or weeks before the census enumerator called. Three children were mourning the loss with their father – Jane aged 10, Mary 6 and Joseph 4. The other three children were not at home on census night, but Elizabeth would die at the end of the year, aged 9, and John, 11, would be William’s only help at home in 1861. William gave his occupation that year as Master Shoemaker. Ten years later he is, curiously for someone so far from the sea, a Marine Store Dealer. (The nearest water of any depth to his home village is the River Swale at Catterick Bridge, three miles away.) In April 1881, living alone, he tells the census enumerator he has retired from making shoes. Before the year is out, he is dead.
William SAYER, the shoemaker, is on the Shared Tree, with a middle name (Benjamin), sleeping with fisherman’s wife Susannah, and being a father to seven of her thirteen children with the other William.
You will notice that William Benjamin has a second-choice wife, one Mary WAGGETT, the woman I introduced earlier. She has a first-born, Benjamin, who I didn’t find in my searches – but he has 33 sources attached to his record so perhaps he is to be relied upon. Benjamin was born before Civil Registration began but all his siblings are found in the GRO Birth Index.
The fisherman, fortunately, has a duplicate ID placing him with Susannah and three of their children. I will increase their complement and add the headstones I have for the extended family, leaving the “bigamous” shoemaker for someone else to deal with.