Some people are truly emotionally unavailable. That means they can't be emotionally available to anyone, no matter how great he/she is. It might have been to do with childhood traumas or upbringing or there are some other psychological damages that cause them unable to connect with another person on a deeper level. This can be temporary or permanent.
If you have established that he is truly emotionally unavailable, it is up to you what to do. Can you accept him the way he is with the amount of intimacy and emotional expressions he's able to give you? Can you be contented with the little you have in terms of passion and affection? If not, it's time to move on to the greener pasture.
Am I Just Being Used For Sex?
The number one concern among women will be a relationship of convenience, i.e. a casual relationship in which she invests more than he does yet she feels she benefits less than he does, mainly because he has all the sex he wants and she gets very little in return in terms of security and commitment.
And to a woman security is everything, while to a man his freedom, independence and autonomy come first.
Let me tell you something, the more you are relaxed about sex, the more alluring you become. By that I'm not saying: be promiscuous or sleep with any man you date. And for sure relationship based on convenience does happen as I can personally attest but if you have faith in your own value as a woman that worry can be minimized.
For most guys, though sex is important they will rarely come back for more for an extended period of time (say more than a few encounters) unless they truly like you.
Why? It's just not worth it in the end since most know that nothing comes free in the end. The potential of drama and hurt feelings far surpass the benefits of having regular "easy" sex. And it's even more so if the woman constantly puts them on alert of the status of the relationship.
Most men understand there is virtually no NSA (no string attached) sex after a certain amount of time has passed. When she begins to show signs uf discomfort of the lack of clarity of the relationship, most men will quickly leave the scene unless they really like her. And if she has been somewhat a nag and yet he's still around, obviously he likes her more than just sex.
So while this notion isn't foolproof by any means, that should enable you to relax a bit about the notion of "being used" which is a phrase that only women with lack of self-esteem and self-confidence will use. A high-value woman feels secure and confident about her desirability simply on the virtue of that she has faith in herself, if nothing else.