Am I developing a negative pattern in relationship ?

Hi,
I'm looking for advice!! Please help!
Ok here is the long story shorted!
I'm 29 and have never been into a serious relationship. Never ever officially had a boyfriend!!!
Early in teen I was a shy girl that now have become a successful confident and attractive woman. But the problem is for the last ten year I have developed crushes on guys who seemed to have interest in me but who never wanted to commit or just playing. In other words I easily fall in crush with guys who are emotionally unavailble. I had no port unities for meeting good men earlier but now I have. Still all the guys I meet are either already taken or too shy or too unavailble. I develop crush on them, try to talk to them only to find that they are not interested in me and then finaly withdraw. I also have another side that I' am too kind where everyone come to when they have problems and then they disappear. I'm quiet not happy the way it is. Why are they not consistent? What should I change? I want to be strong! I'm not desperate to find a relationship but logically I would need a life partner to join in hands with me. What should I do? How come everyone around me get it and I'm not. What should I do to change my pattern? I don't want to be a woman who praises guys! I am looking for a gentleman to pursue me. I think it's quiet reasonable. What should I do to change current situation?any proven techniques or advice?
Thanks in advance.