Summarize the following:
It can be hard to just stop talking to someone who was once important to you. However, if you want to move on and heal, this is a vital step. Stop texting, calling, or seeing him at social events. Avoid looking at his social media profiles.  You do not have to be friends with your ex. However, if you want to maintain a friendship, acknowledge you can't do so right away. You will both need space, so mutually agree not to see or contact each other for a while. If you have to see him because you work together or go to school together, you can be cordial without going overboard. Be polite when you see him, but do not engage in small talk or banter. Try to have as little contact with him as possible. It can be hard to completely stop thinking about someone. If you're thinking of him, and think to yourself, "Stop thinking about it,"  you're only going to think about it more. Instead of beating yourself up for thinking about him, look for another way to direct your thoughts.  For example, find something else to focus your thoughts on. Is there someone new you have feelings for? Try thinking about this person. Think about what it would be like to date them, and what kind of relationship you could envision with them. Redirecting your thoughts is more likely to get rid of unwanted thoughts than simply trying not to think about someone. The mind is a busy place and needs to be occupied, so give it something to do rather than trying to shut it down. Give yourself 90 seconds to allow negative emotions to run their course. Once you've taken 90 seconds to breathe and experience, you'll be better equipped to put your ex out of your thoughts.  When you feel yourself obsessing, stop and start breathing for about 90 seconds. Take about 15 very deep breaths during this time. Breathing will help you allow your emotions to flow through you. After 90 seconds have passed, you should feel calmer and more grounded. The mind needs something to think about. If you can't stop thinking about your ex, use your imagination. Picture a soothing scenario, even a fanciful one, to remove thoughts of your ex.  Imagine, for example, that you're at the bottom of the ocean. Think about the soothing feeling of the water and watching the fish swim past you. Have a variety of soothing scenarios in the back of your mind. When you're bothered by thoughts of your ex, indulge in one of the scenarios. If you are still hanging onto some items that belonged to him or that remind you of him, then it is a good idea to let go of them or at least get them out of sight. If you are not ready to throw away things that remind you of him, then at least put them into a box and hide the box away somewhere that you will not see it.  You might even ask a friend to hold onto the box of items for you so that you are not tempted to look through it. When you're hurt, you may strive for an explanation. You may find yourself trying to explain why your ex behaved in a certain way. These thoughts can very easily get out of control. When you feel them coming, remind yourself of what you don't know.  What would happen if someone tried to explain your thoughts and actions? Would they be able to completely explain what you were going through or experiencing? Probably not. It's not fair to try to explain your ex's actions. You cannot fully explain what he did and why. When you start searching for explanations, pause and think to yourself something like, "I don't know why he did that so I should not dwell on it."

Summary:
Cut off contact. Switch your focus when you start thinking about him. Do deep breathing for 90 seconds. Imagine a soothing scenario. Get rid of items that remind you of him. Remind yourself you can't explain his actions.