This is an attempt to respond to criticisms of my initial response here.
I guess I should begin by saying that love is, at its root, the most powerful most dangerous, most constructive, most destructive force in human life. It is also the most mysterious. Who among us can really understand it, define it, even delimit it?
I would add that I believe love is not a thing in and of and for itself. It is, rather, a process. One can fall in love - the hormones and pheromones and even sun and moon and sun can line up just so between two people - and out of love - God, does she have to do that again? I hate it when she does that - quite easily. Really loving another human being, letting that other person in to one's life, making room for the possibility of personal transcendence, is something that takes time, involves huge risks, and offers the possibility of learning how to be more than what one could ever be on one's own.
In that regard, I believe love to be, at its heart, not an emotion, but the mutually active give and take between two persons wholly surrendering their individuality toward the final goal of becoming something more. As the quote from McCullers seems to indicate, love is not something between an active lover and a passive beloved. That process I tend to think of more as infatuation; one makes of another human subject an object of one's private feeling and emotive actions. That this object may not have any of the qualities assigned to it by the subject is beside the point. We imbue objects with whatever wish-fulfillment we have at any given time. Over time, however, we may discover how short the object falls from our ideal; no individual can possibly carry the weight of another's desire to be something he or she is not. Disappointment leads to rejection.
Allow me an example from my own life. In the fall of 1991, I met and started dating a lovely woman, funny, smart, talented, gifted, gentle, passionate. I found myself, quite beyond any power I possessed, falling in love with her. I opened myself to her completely, utterly. When we broke up just a few months later, I was devastated. In discussing the issue with some mutual friends, one made the observation that this woman was, as the phrase has it "in love with love". I thought about that and realized that, while she may indeed have felt deeply for me, she was even more interested in that state of sublime, intense passion, that connection between two people. She could break off our relationship when she determined that I had failed to live up to her understanding of what was involved. Had I failed her as a lover, or as a beloved? As a lover, no more so than most human beings fail others in relationships. As a beloved, however, that passive recipient of another's subjective desires, I had failed so deeply that there could be no repairing the damage.
After seventeen years of marriage, I have learned that one doesn't really understand what love is. I can say with some confidence what is not. It isn't sex - a person can do that with anyone. It isn't the yearning after another in the quiet of one's heart and mind. It isn't even, in the end, about happiness. It is, when all is said and done, something one learns to do, always imperfectly, but always with an eye on the goal of mutuality in surrender. One takes the other's surrender with the understanding that, in so doing, one is also trusting that other to accept one's own.
I might also add that, disdaining love as an emotion, preferring it to refer to something lived between two people, the issue of "unrequited love" seems to me to denote something akin to Wittgenstein's "private language". I may hold an infatuation in my heart for another individual. I may express that infatuation, only to have it rejected. This isn't "love", any more than me attempting to communicate to another individual in a language that exists solely in my head is actually communication.
I am not disparaging love, I think. I am only saying that it is a real, existing, living thing between two people. Other kinds of romantic attachments, feelings, even acts - even marriage - are not love. I also don't think I am describing some unattainable goal. Perhaps I was a bit too curt in using the phrase "romantic claptrap", but I hope I have at least made my position a little less unclear.