Aoife, thank you again for this most enjoyable and interesting story. My James Wynn was born in Worcester c1761-62, lived in Falmouth, Cornwall until he died in Plymouth, Devon in 1849. That James was a noted Falmouth hotelier and founder of Falmouth's gas industry. He married Grace (nee Eales).
James & Grace had ten children including Mary Wynn born c1796-97 and George Huxham (not Humper) Wynn born 1804, both born in or close to Falmouth.
I have George Huxham Wynn marrying Julia and with a daughter Anna Maria Wynn, agreeing with your romantic story.
I have Mary Wynn (born say 1796) marrying Edward Martin in 1824, no issue, but I have no record of my source. In your story Mary Wynn marries Daniel Frizoni (Frazioni?) di Celerina in c1852, he at age 91 and she at age 56. Maybe the marriage to Daniel was Mary's second.
Aoife, can you tell me where Daniel's family was living (presumably Italian Swiss)while Mary was governess and where the c1852 marriage took place?