Solitude of Friendship

I'm making a discovery about life and friendships. It seems nearly impossible to make or maintain friendships during the middle or later part of one's life. This may not hold true for all, but appears to be a very strong and resounding theme for myself, my co-worker and my elderly mother. I am in my mid thirties. My "closest" friends live hundreds of miles away. They are living on both coasts actually and my dearest friend lives in another country. Explain to me how we have been able to maintain our friendship for the past 15 years despite having seen one another only once during those years? Is that they key to friendship?? At the same time, I find it particularly challenging to maintain any friendships which have origonated in the past 5 years. Granted, the biggest of life's changes have occured during those 5 years taking all of my attention away from those friends (babies have a way of doing that). But again, those friends from far and wide are the ones I still speak to. The ones I exchange Christmas gifts with. The ones I refer to as friends.
Now I look at the art/struggle of making new friends at this age. My co-worker and I have had lengthly conversations about our mutual desire to acquire more friends. Couple friends. Friends with kids. Someone. Anyone. We hardly have enough time for our spouses, but we still think it's important enough to continue to pursue these elusive friends.
My mother and I recently discussed this dilemma and discovered that although there are 40 years between us, we are experiencing many of the same issues. We have held on to those close friends we made in our early twenties, only to have seen the rest come and go as if everyone else has served their purpose and moved in and out of our lives as needed. Is that ultimately what friendship becomes? Perhaps I was mistaken when I thought it was to provide companionship, but even with technology, there isn't a great deal of companionship offered in an email from abroad. Is this ultimately what I have to look forward to for the next 40 years as well? People I call my Friends today will weave in and out of my life so that when I am 74 I will once again feel lonely and crave companionship?

How is it that I feel lonely when I'm surrounded by people all day?

I reach out to some, but they sense that the hand I am reaching out to them is empty.

How do I fill it?

Do I reach out to the right person?

There must be someone able to help me fill it.

It can't be mine alone to do.

I'm alone.