there is no reason to be worried but I bet you are falling in love and now worried he doesnt love you. You can enjoy the man and if it happens it happens or you can worry and stress about it and will eventually make your self so miserable that you will end up chaseing him away. Now i know you probably wont listen to a word I am saying so just go ahead and break up with him and save both of you alot of problems
If it made him happy, why be worried?
Some people are more verbal and straight forward than others. Some people are more open about their feelings than others. The fact that he is happy about it, is a sign that he feels the same way. He may not know how to verbally express himself yet. Give him time....don't rush it