KAknight, did this 'friend' intend to betray you?
or was he just STOOPID?
I've been betrayed before, but to me the difference is the INTENT.
Some people are just careless. Forgive, them, because they just don't know any better. (and zip the lip around 'em next time!

)
Then again, some people will trade your trust for some other (percieved) advantage...these people aren't worth the fat to fry 'em in hell.
Perhaps the test would be...sitting this person down, and finding out how they feel about what they did?
Their attitude about it will tell you everything you need to know.
Hang in there, buddy...