Well first, realize that a lot of times, we really aren't feeling much of anything. Second, we don't connect with people on an emotional level. As pointed out above, we do it on an intellectual level. A lot of the times, emotions don't even cross our minds. Experiencing emotion is not our natural state, so if you ask us what we're feeling, our honest answer would be something like "not much". When we do experience emotion, it takes some private analysis to figure it out, and furthermore, we don't particularly enjoy expressing our emotions. We like to keep them to ourselves. They're a very private thing for us, and it simply doesn't cross our minds to show em to others, and when we do, it feels unnatural. We're basically exploring uncharted territory whenever we do it.
However, this doesn't mean at all that we don't like you. I suggest learning to recognize how he shows his appreciation, which is basically just by spending time with you, interacting with you, and letting you in on our interests.
But clearly, you have your emotional needs. It wont come naturally, but we can learn to recognize and reciprocate emotions. It'll be a slow process, and likely feel very unnatural and uncomfortable for him. You could help by being open with your wants. Don't try and be subtle, it's quite possible he will miss it entirely. Just spell it out what you want, and (assuming its a reasonable request) he'll probably be glad to oblige, and relieved because the uncertainty is gone. Eventually, and very (very) slowly, he'll feel comfortable with sharing his emotions with you openly, but even then, remember that we don't experience them as often.
imo