My grandparents are a classic Darby and Joan couple.
Darby and Joan
idiom Slang
Cockney rhyming slang · East London
moan
Origin
first recorded 18th c.John Darby and his wife Joan were first mentioned in print in a poem published in The Gentleman's Magazine by Henry Woodfall in 1735.
After fifty years of marriage, they are a true Darby and Joan, rarely seen apart at the local park.
The elderly pair lived as a devoted Darby and Joan, finding quiet contentment in their shared routines and long, peaceful walks.