How can I teach myself to be a more affectionate, loving person?

I have been a cold, standoffish person all my life. I seem to have a hard time showing certain emotions. I come from a large Italian/Portuguese family, and when greeting each other, we are supposed to hug and kiss each other on the cheek… but I have never been able to. I have a boyfriend and I can kiss him and be intimate with him, but he always has to initiate it. I think this causes a lot of problems in our relationship, and also other relationships like with friends and family, as it makes it seem like I’m cold and aloof. I’ve always tended to keep to myself. I think a lot of it stems from my intense fear of rejection or being hurt. I tend to push people away, because I’d rather hurt someone than be the one to get hurt… if that makes any sense? Anyway, how can I learn to be a warm, loving, affectionate person and not be so awkward?