If this quesiton does come about from him again why don't you first of all state, he is your good friend for a reason, he is one of your boyfriends best friends and you do NOT cross the line when it comes to your friendships. You cannot create feelings and you believe in honesty.
Another suggestion, knowing he has these "feelings" for you, it is not a good idea to keep going to him when you have issues/problems with your boyfriend...I had a situation where a guy friend of mine also started to develop feelings for me that I just didnt have for him, it progressed to him getting to the angry stage then a "stalking" stage.. I had to totally cut him out of my life.. I return NO phone calls, text messages, etc....
You may have to do just that, NC with him at least until those feelings he has for you get back to the "friend" zone!
I wish you well.