In fact, after a friendship of love is not the case, as well as the friendship between a man and a woman. The only way to preserve the semblance of peace - it is neutral. If you work together, or you have children together, make this a must.
The first thing to realize is that no one is to blame. People do not leave just like that, usually it is not a decision one day, and the prerequisites for the break occurred be long before the sad event. To all fell into place, you need to calm down. Try some time not to see. If you bind a single place of work, and you can not quit, take a vacation at least for a couple of weeks. Read, sleep, eat. It does not matter what you'll be busy, most importantly - switch.
Now that you have calmed down a bit, try to understand that no one owes nothing to. If you have initiated the break, and do not reproach scold yourself, do not try to explain anything to her former "second half". All eventually fall into place. In case you leave, keep calm complicated. However, we should not forget that we are all free birds, and the fact that someone goes with you nothing will happen. Respect one person in a relationship. It does not demand from him an explanation, anyway, none of them suit you in full.
Love yourself and do not look for the reasons. Historically, because of what was going to happen. Learn to let go. Let people not with you, but in fact it was not only bad, it was a lot of good. Remember him with gratitude and love. Suppose you now hurts, but not intentionally inflict harm to another. Without saying a word, which later will regret.