Accepting that your relationship is over is the very first step after a break up, and without this realization you'll be hard pressed to move on. Now is the time for renewal, not hopes for reconciliation. Sure, there may be a slight chance the two of you will get back together, but even the most astute 'get your ex back' manuals start with this first simple step: take a break.
Give yourself some time to mourn your loss. Get to know yourself as a single person. Toe your lines of independence and find out what makes you happy again. Staying friends with your ex will only prolong the pain. Think of any interaction with your ex like an addiction -- every single time you succumb, it'll be that much harder to refuse later.
Keeping Remnants of the Relationship
There are quite a few things considered 'remnants' of a relationship, including photos, cutesy trinkets, mementos, clothing, and even food. After a break up, especially if the two of you have children together, it can be challenging to remove all of these items from your home. Luckily that's not what I am asking you to do. Instead, fill a box with whatever items you feel will be necessary at some point in time in the future but still remind you strongly of your ex, and then put that box in a private, out-of-the way place for the time being. There will be more than enough reminders on a day-to-day basis of your ex just because of how the human mind works. You won't need any extra help to add fuel to the breakup fire.
Ignoring the Negative Emotions That Surface
There is no doubt that you will feel strong emotions after a break up, such as loneliness, anger, fear, shame, uncertainty, humiliation, sadness, despair and jealousy. For many, these feelings will also surface physically, like crying or feeling like your heart is breaking.
Not only are these 'negative' emotions healthy, but they are important to feel in order to remain healthy. Sure, they seem miserable and probably don't make you feel better in the moment, but allowing yourself time to grieve is an important part of healing after a breakup. Plus, a scientific study undertaken in 1980 by Margaret Crepeau found that frequent criers are healthier people. So don't be afraid to comfort yourself via expressing your negative emotions.
If there were issues related to addictions, abuse, mental health (i.e. depression), or self-mutilation prior to your break up, please seek out professional help to assist with your specialized needs. (See: How Do I Find a Therapist?) The same goes for those finding themselves using drugs, alcohol, sex, cutting, or any other harmful self-medicating behaviors to cope with the pain after a break up. And if you feel the need to hurt yourself or someone else, please call a crisis hotline immediately.
Beat Yourself Up
Most people's basic needs are the same: food, sleep and protection from the elements (i.e. shelter and food). During a particularly difficult break up, some people aren't able to manage even these simple tasks -- which is understandable, although not acceptable.
If you cannot be your own best friend right now, ask for help. Talk to your friends, family, a counselor and/or loved ones and let them know you may need a bit of extra support in the next little while. Additionally, create a break up action plan to post in key places, such as on your fridge or hidden away in your desk at work. That way you'll have no only have people checking out for you, but you'll also have created a foolproof list of things that make you happy to refer to.