My husband doesn't show his emotions. Can you tell me why is it so?

My husband doesn't show his emotions. Though he cares for me. But he never says I love you, i miss you and things like that. He is into merchant navy and goes offshore every two months alternatively. We recently got married (in feb 2010). When we chat or talko n phone I don't realize he is missing me. He never says that. Though he cares very much. I often say I love you to him but he doesnt reply. Why is it so? Should i keep on telling that i love him or I should behave the same way he does? I send text to him, I send mails to him but he replies for one against 10.