I think its great that you two have such good communication. And I'm jealous about the walk across the Brooklyn Bridge. I really need to make time for a trip to New York.
Oh my... I say just go and tell it to him straight. I'm not looking forward to the day I have to do the same with mine but it has to be done. Just know that he'll appreciate you coming to him and having that discussion even if he doesn't say so. In my experience kids can handle a lot more than we give them credit to. It'll probably be awkward but you two will benefit from having that convo. Be blessed.