Phil:
The third record at the link below shows the 1920 civil marriage record. Patrick Myers was a widower and was living in Clones at the time of the marriage. The names of the fathers of the bride and groom are also shown.
https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_ret...
I located the 1921 birth record for William Myers (first record). Birth records for children from 1922 on are not available online for privacy reasons.
https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_return...
I checked the 1901 and 1911 censuses and did not find a Patrick Myers in Co. Monaghan.
I did locate an 1918 marriage between a Patrick Myers and Rose Anne McCaffrey in Clonses
https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_ret...
Rose Anne died in 1919
eighth record Rose Anne Myers https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_retur...
Roger McDonnell