sadder but wiser
Unhappy but having learned from one's mistakes, as in Sadder but wiser, she's never going near poison ivy again. The pairing of these two adjectives was first recorded in Samuel Coleridge's The Rime of the Ancient Mariner (1798).
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.