"Maud Muller" is a poem from 1856 written by John Greenleaf Whittier (1807–1892).
The judge marries a woman of wealth whose love for him is based on his riches.
This poem contains the well-known quotation: "For of all sad words of tongue or pen, The saddest are these: 'It might have been!'"
Whittier's younger contemporary Bret Harte wrote a short parody and sequel to the poem entitled "Mrs. Judge Jenkins", which mocks Whittier's conclusion by having Maud marry the Judge after all, with far more disastrous results: Maud's relatives get drunk in the wedding, while Maud herself grows "broad and red and stout" after giving birth to twins.
[1] Harte juxtaposes Whittier's famous line with his own, witty, take: If, of all words of tongue and pen, The saddest are, "It might have been," More sad are these we daily see: