This makes me so sad. I met the most amazing person I'll ever meet on the internet. She lived in Switzerland and she was just incredible. The most talented, coolest, gorgeous person I have ever known. She was super confident and I had zero confidence. We liked each other so much and always mailed, texted, phoned sometimes. She'd always text me in the night and she made me feel so amazing and happy. She wanted to meet many times but I was too scared too so said I couldn't. I kept thinking to myself 'I will meet her when I get over this SA'. But I still haven't overcome it. We were close for 8 years but about 2 years ago she met some guy and the mails and calls and texts starting drying up. We no longer contact each other, we didn't end in bad terms whatsoever but she clearly was so in love with this guy and she totally lost interest in me. How I miss her! : (
So to answer your question, I think it can work but you have to meet the person regularly. It is the same with friendships from a distance, usually if rarely see the person you will drift apart.