So, if we remember that we cannot undo what’s done, we can improve the quality of our thoughts and thus make life easy for everyone around us. You can never undo what’s done, so why be regretful? Without much ado, try to not to undo what’s done. When you know you can’t change something, you tend to accept it - regardless of whether you approve of it or not. They can’t get over their partners’ adultery but want to continue with their marriage..