We all have them and they have all taught us lessons about life and ourselves, exes. They all stick with you in some way that reminds you why you aren't with them anymore. Some people break-up and stay friends while others choose never to speak to one another ever again. I've had both types of break-ups. Regardless, every ex has a story and a lesson.
A lot of the lessons we learn from break-ups is what we don't want in a significant other. Whether it's an annoying habit like smoking that's a deal breaker, or just a personality trait that doesn't mix well with your personality. I'm an ambitious and independent person.
I have an ex that taught me I want someone whose not clingy and has their own goals in life because he was very much about making sure everything one of us did included the other. While your significant other should play a big role in your life, you should still be able to have your own friends and your own goals.
Another lesson you can learn from a break-up is that people are not always what they seem. I had a friend whose ex's true colors came out when they broke up. He ran around talking about her like they had never even been together.
People can be mean and ugly but sometimes you don't see it until it is too late. Next thing you know you are working against a reputation that your ex has made for you simply because they felt hurt that you found out you didn't need them anymore. If anything though, the fact that they are talking bad about you should reaffirm that you do not need them.
Another thing you learn from breakups is that you shouldn't listen to your friends when it comes to picking your significant other. They might think they know what you need but they really don't and sometimes they are just as clueless as you are about someone's true colors. They are coming from a good place but only you know what you need in a significant other and have the ability to determine if someone fits the bill.
Exes come with a lot of responsibility and while it is upsetting at first having to break up with someone or be the one being broken up with everything happens for a reason. We live and we learn and that's the way it should be.