The way to turn an ex-lover into a friend is to never stop loving them, to know that when one phase of a relationship ends it can transform into something else. It is to acknowledge that love is both a constant and a variable at the same time.
I hope you will go out and let stories, that is life, happen to you, and that you will work with these stories... water them with your blood and tears and your laughter till they bloom, till you yourself burst into bloom.