I think anyone who opened their heart enough to love without restraint and subsequently were devastated by loss knows that in that moment you are forever changed; a apart of you is no longer whole. Some will never again love with that level of abandon where life is perceived as innocent and the threat of loss seems implausible. Love and loss, therefore, are linked.
People change us. It is a rare, if not an impossible occurrence, that we come out of relationships unscathed. In our dealings with people we take something with us and we leave something behind. Some people are haunted more than others, either by the sweet perfume of another or the stink of regret.