"Ulysses Annotated" by Don Gifford has this entry:

14.1419 (423:35) Darby Dullman there with his Joan – Darby and Joan are an elderly couple who live in marital felicity, indifferent to the society of others, in Henry Sampson Woodfall's (1739-1805) ballad "The Happy Old Couple; or, The Joys of Love Never Forgot." The speaker tells his "Dear Chloe" that they must love in their youth in order to enjoy in old age the "current of fondness" that is shared by "dropsical" Darby and "sore-eyed" Joan, who still "possess" neither "beauty nor wit."

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