Look, I don't want to sound like some patronizing 40 year old, but there really ARE other fish in the sea. Seeking revenge is pissy and irresponsible, and life is all about responsibility. I'm sorry, but it is.

You like this girl. Hell, maybe you even love her. I won't judge you for that. But she didn't love you the way she loved your friend. It's her right to date whomsoever she wants, and your plotting revenge against her choice is equivalent to pissing on her face. You are disrespecting and humiliating her, treating her like an object to be possessed. And for THAT, I do judge you.

Grow up, kid.