Is it okay to tell someone you miss them?

My friend and I have known each other for a little bit, and things got flirty and romantic while he didn't live here. We would chat online almost every day, and it was comfortable and sweet. We would talk about everything and anything. Time comes for the first date, and it was wonderful, except it might have moved a little bit too fast, and now things are a little awkward. He was in some seriously bad relationships, and he has lots of trust issues. He insists that everything is okay, and we're still going on dates. But he's cold and detached, not warm and sweet like he was before. I don't know what to think of it. He's a kind person with some baggage, so I think he would tell me if he didn't want to be with me anymore. I want to be cool. I want to give him what he wants, but his behavior is hurting me a little bit, and I feel sad and confused. I want to know if it's okay to tell him that I miss him, and how to do it without sounding like I'm annoying or whining. :( Thank you.