Here is what strikes me about this conversation. You say he wants every other part of the relationship other than the romantic aspects - but frankly that does not jive with someone who doesn't want to be "blindsided" when he finds out you are dating. "Blindsided" seems like a strong term for him to use. He sounds like someone who does not know himself well enough right now to know what he wants.
Which leaves you to ponder how long you will wait for him to become self aware (and who will he end up being). Its a variation of so many stories on here, which is why all the emphasis on what you can actually control. I would keep on doing what you are doing.
