Why do I seem to be incapable of (showing) love?

I’ve been like this ever since I can remember. Cold, kind of aloof… and flat out unaffectionate. And I don’t know why. But I hate it. I’m trying to figure out the root of this problem so that I can make steps towards becoming more loving and affectionate. I have always been shown love from my parents. They have been married 21 years and have been fantastic parents to my brother and I. So I don’t think that’s my problem. I think the problem is me. I don’t know if it has anything to do with having cancer and resulting health problems since a very young age. I have always felt different from my peers… More mature, I suppose. With a different perspective on things. However, this has never really affected my friendships… so how would it affect my intimate relationships? Basically, I feel really awkward in romantic relationships. I don’t like being touched because I’m just so insecure with my body. I don’t initiate any sexual activity, not even so much as a hug or a kiss. I’m afraid to. And in other relationships, such as with family members, I don’t like giving or receiving hugs. Not even from my parents.
I want to know what is wrong with me. I have a history of depression and social anxiety disorder. For which I’ve been through a year of cognitive behavioral therapy. I no longer have a psychologist. After my CBT, I pushed myself out there and now I am more confident and outgoing than ever before…but we never touched on my love and affection issues because I’ve never really noticed it until now. How do I get over this? I’m tired of being a cold fish.