I am sorry that our friendship, or whatever name one may give to the obsessive relationship which has bound us together for so many years, should end in this way. This is not the place to utter its elegy.
Circumstances, luck, mutual need, affection and time played a part. No relationships were made in heaven. They were made because living things were looking for good company. And when you found good company, you valued it deeply and were responsible for its up-keep and well-being.
The people you meet in your life, you meet them for a specific purpose: To help them and to be helped by them. So, try to spot the treasure in your everyday life, because one day you may realize you had the treasure and you lost it.