A Broken Heart...

It has been sometime since I've written, and I don't know if anyone even reads anymore, but I'm stuck, and don't know what to do, where to turn, so if anyone still checks in occassionally and has some insight, I'd love to hear it...
Here's the situation in a nutshell: I've been seeing a wonderful woman for the better part of a year now and things are good- on the surface. We have a strong friendship, much stronger than our relationship, which is good. We enjoy each other's company. We communicate regularly, and well. But here's the problem...
I learned long ago that there is inherent danger to making oneself vulnerable to loving again. The possibility for hurt, for disappointment is ever present, but not to be vulnerable robs one of something so much greater than the potential hurt. To love and be loved is the greatest of feelings. So I made myself vulnerable, and I fell in love again. As I learned her good points and her flaws I loved her for them. Unfortunately, my new love tends to close herself off to those deep emotions, choosing to remain behind self-imposed walls to "protect" herself from hurt or disappointment. We've discussed it- she doesn't even want me to say I love her, because she's been told in the past and now doesn't believe it. On rare occassions (maybe 3-4x this relationship) she's told me she loved me, but then is quick to make light of the moment, or retreat behind her emotional walls. I've showed her in many ways, many acts, how I feel, and the validity of my words are backed with actions, but to no avail.
I feel like I am being robbed of something precious, that my emotional needs are being sacrificed for the sake of her unwillingness to believe, to open up... Once she told me I was the best thing that's ever come in to her life- so why does she chance losing that by pushing me away aand closing me off emotionally? I don't know. I can't imagine my life now without her, but I can't continue on giving without receiving that emotional connection in return... Sooner or later my tank will run dry and there will be nothing left to give; if I leave it justifies her emotional walls (to her) and I become like those who said in the past "I love you" but didn't really mean it- because I too left. I don't think the idea that she pushes me away emotionally really occurs to her as a possibility to destroy our relationship... And yet she's told me that she realizes I might not be getting everything I need out of our relationship, but she isn't willing to give more right now...
My heart is broken, often, when I leave her, for there is nothing worse than leaving the one you love and not being able to remind them of that love until we meet again. No, there is something worse; it's loving someone and never hearing they love you too... So what do I do? Where do I turn next? Despite all the good in this relationship it is doomed to failure without that emotional connection that flows both ways... I've been patient, but now I find my tank running dangerously low, and my thoughts of what a fool I am to open up myself to yet more heartache in my life... When questions like "Is it worth it?" start arising then perhaps it's not... Food for thought...