How do I come to terms with this feeling of betrayal?

Oh, Boy.

I have/had a work friend that I have known for almost 4 years. He was the only person I really talked to about non-work things; we were friendly. He is so intelligent, nice, mellow, always helpful and polite. Just a good guy.

Yesterday my bosses start changing the locks and garage key codes and I am told that my friend is getting fired. Later I hear about the reason and I am flummoxed and incredulous. What happened is something that I could have never seen this guy doing in a million years. It’s pretty bad and to me a reflection of a not so good person.

I was talking to my wife and I realized that I feel betrayed and like I cannot trust my thoughts and feelings about people. This has never really happened to me. I feel like I’m usually a good judge a character, especially regarding someone I’ve known for like 4 years.

Has this ever happened to you? How did you come to terms with these feelings? I always say you never really know anyone and I guess that’s true, no matter what. Are all men really pigs, underneath it all? I already have trouble trusting people. I’m just so confused.

Help? (General Question)