Hi Anon, to be honest with you i don't think it's to do with either telling him and risking the loss of a friendship, or, keeping your feelings inside and bottling them up. It is more to do with having to tell yourself that those feelings have to go, not bottle them, but to dismiss them.
It's very easy for me to say this as I have had the benefit of many years experience. I also except that when one has feeling they are often very difficult to put in the back of ones mind but from what you have told me, either of the options you mention are probably of no use to you.
If you can learn to accept that you simply cannot have this guy in any other way except as just friends - learn to accept this and feel any sadness that this may bring, then surely this is more healthy for you than to either risk destroying your friendship or beating yourself up by harbouring feelings.