Couldn't you have just told your sister and kept your identity secret?
In addition to sending a note to my sister, he had posted it publicly. It was just a matter of time before people found out. On top of that, now that it's out there, he has nothing he can hold over me if he gets pissed off again. It's for the best.
I realize it can potentially fuck with job prospects in the future, but again, I'd rather this happen on my terms than on his.