I have been looking for this couple off and on for a while now and since a previous comment quite some time ago in "Great Orme Cemetery", I think, I have a little more information, which may help in my search.
Thomas WILLIAMS was born probably Caernarvonshire, may be Caerhun/Rowen. He was a shoemaker.
His wife Emma was born about 1772/75 in Caerhun as stated by census returns in 1841 and 1851. Thomas and Emma would have married some time around 1814 or earlier having their first known child baptised in 1814 at St. Mary's in Caerhun, (I have the baptism record). This was their daughter Mary. They are noted as living in Ro-Wen with Thomas noted as being a shoemaker. Their son John was similarly baptised in 1817 (I have his record too).
Son John was usually noted as being from Rowen or Caerhun on his subsequent census returns.
In 1841, Emma is found at Chapel Street, Tre Y Dre, Llanrwst, Denbighshire with Mary and John but no sign of Thomas, her husband. By 1851 Emma is in Scotland Street, Llanrwst, Denbighshire with her daughter Mary and presumably Mary's illegitimate daughter, Mary PRITCHARD. Emma is noted as a widow. She died at the same address in 1860 at the stated age of 88, noted as widow of Thomas WILLIAMS, shoemaker, with son John in attendance. She had at one time been a spinning woman.
Mary their daughter,never married as far as I can tell, dying about 1887 I believe in Llanrwst. Mary's daughter Mary Pritchard may have married John LLOYD about 1875 in Llanrwst
John, Emma and Thomas' son married before 1865, to whom I know not and then married Martha ELLIOTT of Daventry in 1865. He was a gardener and became the publican of the Telegraph Inn on the Orme as mentioned in other forum messages. I still am not sure of John's whereabouts in 1851 or the identity of his first wife.
ANY snippets of information gleaned would be MOST welcome as this has been a huge brick wall for me. I have found virtually nothing about Thomas and only what I have mentioned on Emma. Hugo has very kindly checked Caerhun marriages for Thomas and Emma previously but was unable to find anything that fitted. Since then, though I have more of an idea of age of Emma at least. Keeping my fingers crossed