My Girlfriend doesn't think i'm affectionate enough?

I've never had this problem with other girls I've dated. The girl i'm seeing now doesn't think i'm affectionate enough. I dont need as much attention as she does and I'm perfectly functional that way and very happy. She on the otherhand is miserable. She says that i'm heartless and dont care about anything which really hurts. I'm a fireman and i consider myself very caring. I do think that if i was a very emotional person like she is i wouldn't be able to handle the things i see everyday at work (I see a lot of horrific things as a firefighter). I know i might sound shovenistic but believe me I'm not, I cook for her, maintain her car, help her out with everything and basically take good care of my girl like a man should. What can i do to make her understand that this is me and i show my love with actions. I've almost got stabbed once at a club protecting her. Is she being selfish? I will add that she did date "very affectionate" type of guys but they were just as dramatic.