W.T.F.- Why did my boyfriend's BEST FRIEND do this to me?

So teh other day, I was checking my email and all of a sudden, it says I got a new message. I saw it was from my boyfriend's best friend. So I click to open it, waitign to see what he says, and WHAM! I am reading this message about him wanting me to give me a b*** j** because he knows what I "did" last year (Ok, for the record, all I "did" last year was have a sleepover with a couple of my friends, get drunk, go out with only tank tops and shorts on, go to a nearby club, started stripping and grinding against each other, had a [me and two guys] and streak home...That's it.) So, I REALLY don't want my boyfriend to find out about this because he would freak out (like any guy). So, please don't tell me I shouldn't have done it because it's in the past now. Just tell me what to do to have my boyfriend's best friend NOT tell my boyfriend.