Don't Act Impulsively
If your partner says they no longer want to be with you, don't act impulsively and do or say things you will later regret. Give yourself time to absorb your partner saying they no longer want to be with you.
It is hard to restrain your words or actions, but in the long run, you will be better off for it. Don't take a hammer to your partner's car only to land in jail. Or, don't say you hate them out of anger. Revenge almost always backfires.
Seek Support
Talk to a trusted friend or family member about what you are going through. You will go through many emotions. The worst thing you can do is isolate yourself. If your feelings are extremely intense or you have suicidal thoughts, seek professional help.
Accept Your Feelings
Accept your feelings and let the tears flow. Allow yourself to go through the stages of anger, resentment and pain. But, do so constructively and not destroy yourself in the process. Your life is worth more than allowing one person to destroy you.
Be Kind to Yourself
Don't put blame or punishment upon yourself for what you don't own. A breakup does not mean you are not worthy. It means things were not working out. It could mean the person you were with was a jerk or someone you were not meant to be with. Pamper yourself with positive activities and positive thoughts.
Perspective
Put the breakup in perspective. Do you really want to be with someone who doesn't want to be with you? Do you want to be with someone who bails out or who cannot commit? Learn from the relationship and breakup and use those lessons for the future.
Forgiveness
It is difficult to forgive someone who has caused you so much pain. But, forgiveness is about you. It is about healing and cleansing yourself of negative emotions and thoughts that prevent you from moving on. Not forgiving those who hurt you is toxic to your well-being and your future.