I hate my friends

So im back more about the guy i really like. Its gotten intense. So me and him havent been talking for a couple of days. Tonight i found out that one of my good friends is datig him. Im so mad. This girl has sat there for a month giving me advice, swearing she would never go out with him, trying to set me up with him, and now shes going out with him. She doesnt know i know bc she didn't want me to know. I dont exactly know i feel. I doubt she even likes him and the minute i hear she hurts him in any way someones gonna end up in the hospital and its not gonna be me.