I can appreciate that and can be patient if I know he is only dating me.
I think you should tell him. Not in a heavy commitment sort of way because your D looks like it was only final three months ago so you need to give yourself time as well. But I see no harm in telling him that you really like him and would like to date each other exclusively (while taking it all really slow for both of you).
As PP stated, if that isn't what he wants to do it is better to know now.