Finally "got together" with my best guy mate, but now he's gone all quiet?!?

You are beating yourself up and jumping to conclusions it seems. The time frame seems a bit confusing, how long has it been since he has talked to you (intimately)? This may not be good advice, as people are very complex, but i'd say try not to jump to so many assumptions. The relationship between you and him seems to be an admirable one and you should just give it a little time. He will come back to you