It's inevitable that after you break up with someone, he or she will move on to someone else. And it will be painful. But for many women, after they split with a man (usually of a certain age) who then falls into the arms of a much younger woman, it can be traumatic. The first thing to remember is that his choice probably has nothing at all to do with you. Many women blame a midlife crisis for a man choosing to be with a younger woman, but the reasons are myriad and best not questioned. Keep in mind that he is not "upgrading" after being with you. If you consider yourself to be friends with your ex, just leave the matter alone. You know it will only be more painful for you the more you mine for detail - save yourself the heartache by simply nodding and smiling as a means of encouragement if he does bring up the topic of the relationship. Keep in mind that your ex's life really isn't your business anymore, just like your life isn't his business. Don't ask questions you wouldn't feel comfortable sharing the answers to if the situation were reversed. It may be tempting to comb social media for the details about his relationship - and again, put yourself in his position and ask yourself how it would feel if he stalked you for details about your new love. If you've ever heard the term "ignore it and it will go away," it is applicable to this situation. The more you discuss the hurt and anger you feel or discuss the relationship cynically with your best friend, the more you dwell on the situation. Let it go, and you'll be a much better person who will be more open to loving another in no time.