sadder but wiser - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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).