He caught me on accident and he wont trust me?

My bff is a guy and right now im dating one of his best friends. i love my bf very much and would never want to hurt him. one night i was at my bff's for a dvd night with him and my bf... my bf wasnt there yet and it was just me and my bff. suddenly he turned to me and started professing his feeling for me out of nowhere, and just as my bf walked through the door he leaned in and kissed me. i just froze and had no sense watsoever and didnt push him away like i should have, and just sat there llifelessly wondering how i was going to get out of this. my bf glared at me and stormed out of the house, leaving behind the chocolates he had brought for me and the new dvd he had brought for my bff. i dont know what to do! i didnt try to hurt him and now i cant talk to him or my best friend. plz help!