Make an effort reprogram your negative thoughts, tuning in to a positive. Listen: what words you describe what happened to you? Replace with another formulation of an obsession, "I can not bear it! ". Try to step back from their emotions and admit to yourself: "I once had an idea that I can not bear it."
Another way to get rid of heavy thoughts - how to analyze them. Rather than try to forget everything that you are bound, think about what your friend did to save the relationship. Recall occasions when you yourself violate the promises given to the partner, he applied resentment, hurt or did not do what should have been. Of course, blaming the other easier and more familiar, but your memory will help uncover the causes of the incident and, paradoxically, grow cold to the former lover.
Whatever it was, do not look for its own fault, not engage in self-flagellation. Consider what happened, not as another personal failure but as a step towards a new knowledge, as the beginning of a completely different and interesting life stage. Indeed, any loss is any guide, makes a person wiser. So try to learn from this situation. Do not lower the arms and ask yourself: "What can I learn? What to do to wrap everything in their favor? ". It is possible that in the near future and you can not find answers to these questions, but positive thoughts will help you get through this difficult period of life.