The following is from C. S. Lewis' A Grief Observed. The book is a journal he kept during the months after the death of his wife. It is full of anger and anguish, and also in the end, hope.
All reality is iconoclastic. The earthly beloved, even in this life, incessantly triumphs over your mere idea of her. And you want her to; you want her with all her resistances, all her faults, all her unexpectedness. That is, in her foursquare and independent reality. And this, not any image or memory, is what we are to love still, after she is dead.
Reality flies in the face of what we believe to be true -- brings it down like a house of cards. And with the best love, or the best friends, this is good. It is good to have the reality always breaking into your ideas about those you love, and proving again and again how much better the reality is than you can possibly comprehend.