New to dating

So, I've been exclusively dating this wonderful guy who is the most caring, funny, smart, sexy man I've ever met. First time dating since my 15 year marriage ended last year. We've been dating for 9 months and he's met my son and they get along great. He's 38, never been married and never had kids, a lawyer, we both have so many things in common and I could see a promising and fulfilling future together with him. I've met his family and friends and he's met mine. We do many things together with and without my son. And he's amazing in bed! The only thing holding him back is that he's very guarded. He makes commets about how he's single and doesn't ever want to get married. His past relationships have all been train wrecks who used him. I have a doctorate and my shit together, which is something he's never experienced before in dating someone. How do I know he wants to be with me if he makes those commets? Do you think he is just thinking through things and trying to figure out how he's with such a great girl? Is he scared I'm going to hurt him? If so, how do I reassure him I'm not like all the others? Or do you think there's something else going on?