Something similar happened to me a few years ago and we haven't spoken since then. I was the one who started distancing myself from her. She was very untrustworthy and turned out to be someone I didn't think she was. I wouldn't say we were very close (we were getting there and could have been), more like good acquaintances then, but we had our great times and because I valued even the littlest friendships it did hurt. But with my case, us putting a halt to the friendship was the best thing that could have happened -for me. I've another situation (long story) right now where I'm the one putting up a wall right now (totally different story), like your friend is doing to you. So I can say that it seems you've really hurt your friend. I know you don't know what you did, but he does (and I know he won't tell you and that sucks) and he's holding onto that grudge b/c he likely trusted you and never expected that you would do that to him -that's why he's probably still very...disappointed. I was trying to figure out what word to use and was about to use angry, but I don't think he's angry at you, likely just very disappointed that someone he never expected to hurt him has. And if it's now 5 months later, then he still feels really hurt. But I don't know the situation at hand, so these are merely assumptions based on my own experiences. It's likely that he has confided in someone else that you know -perhaps another friend and you could get clues from her him/her. You mentioned friends up there but in the end you focused on one person (He)...so are there more people involved? He might have told someone/one of those other friends. If you were very close and you know they type of person he is (i.e. is he very forgiving or does he eventually forgive..maybe not forget but forgive?) then he'll come around...eventually.
