The expression “to cry over spilt milk” means: To grieve over that which is irretrievably lost or beyond recovery; to regret that which has been said or done.
Though the actual occurrence, with high milk prices, is something over which housewives probably have wept, or over a torn fig leaf, since the time of Eve, they never think of the ones benefiting from the accident, the dog, the cat, or the milkman, just their own selfish loss.
The first to give voice to this cold comfort in this manner, in print at least, was that prime humorist of the past century, Thomas C. Haliburton.
In his first series of The Clockmaker; or the Sayings and Doings of Samuel Slick of Slickville (1836), a friend says, “What’s done, Sam, can’t be helped, there is no use in cryin over spilt milk.”