My boyfriend thinks I'm too good for him and I don't know what to do.

I'm soon to be 18 and my boyfriend is soon to be 21. We have only been seeing each other for about a month but recently he told me that he thinks that I am too good for him. I am currently attending college which he didn't do and he believes that I am more intelligent than him as I use better vocabulary. I really do like him, but he has trust issues as his ex girlfriend cheated on him, and he is constantly worried by men who look at me when we are together. How can I reassure him that it's only him that I want?