Lewis is my BFF

On Friday I admitted being somewhat wary of how strongly and completely I agreed with what Lewis had to say about love and affection. Some of his insights convicted me, others inspired me, and nearly all of them were true of love as I understood it, or at least as I thought I ought to. As I read of his experiences and observations a part of me sensed the revelatory "What you too? I thought I was the only one" so indicative of Lewisian friendship. Would Lewis and I to have lived in Oxford concurrently, I surmised we should have been good friends. And then I read his chapter on friendship. And I am now left wondering if I, in fact, have any real friends at all.
I take issue with several things that Lewis has to say regarding friendship, not the least of which is his laughable view of women. For now I would like to address the "shared interest" so essential to friendship as Lewis defines it. Much quoted is the line "Lovers are normally face to face, absorbed in each other; Friends, side by side, absorbed in some common interest" (p. 61). It is true that a common interest may bring together two who would otherwise not speak two words to each other. The common interest may initiate conversations, lead to intentional meetings and even bring about a society of sorts among those who share a love of it. But such an interest, I believe, can not be the crux of any truly loving relationship. Of course my views of friendship are, like Lewis', based on my own experience with it, but I do not think this such a bad thing.
In my experience friendship involves more intimacy than can be disclosed in a relationship that revolves around a common interest. In such a relationship it seems that the friends serve only as sounding boards or fellow enthusiasts who are not truly concerned for one another as individuals at all. They are as replaceable as a one-of-a-kind coffee mug. Its loss may be noticed, but a replacement will serve the same function, and soon the original will be forgotten altogether. In some sense it is the difference between livestock and pets. Friendship as I understand it requires personal investment and intimacy.
Where is the durability in a friendship that does not show interest in the personal life of the friend? On what basis will it be held together over a period of time if no emotion is invested in the person, but only in the interest? If you love me, will you not care about what happens in my life? Will you not inquire after me and learn of me even as you do our shared interest? If you do not, what is the likelihood that we will continue to meet week after week, month after month, year after year? I suppose it is possible that such relationships could occur. That correspondence concerning the interest and new insights on it could take place indefinitely. But uninterested friendship, though possible, does not seem ideal.
The only way I can reconcile what Lewis lays out with what I have experienced is to return to Lewis' claim that the various loves (Affection, Friendship, Eros and Charity) often mix together, interacting with one another. It may be that what I see lacking in Lewis' concept of Friendship is completed by affection or solved by a good dose of charity. Perhaps charity provides the longevity, or affection the love of the person's peculiarities that would otherwise be missing in friendship. If not, than I am not so sure that Lewis and I could share a friendship as either of us defines it.