In summary, a girl led me on for 8 months of my life. She knew I was totally in love with her, wanted a future and crap and I had a serious liking towards her for 3 years. We consummated the relationship or whatever and she said the whole I love you crap, I want marriage and babies and then out of nowhere she silent treats me.

I message her sister, turns out she had a boyfriend the entire time and got sick of playing me around.

A lot more to it, pretty bitter, and she rubbed it in my face. Really dying to get revenge. She got her BF to block me, so it's hard for me to tell him what happened to then break them up. Found out her dad was on the leaked Ashley Maddison list and I told her about it and she was pretty freaked out knowing I can rip her family apart.

Do I print out the Ashley Madison stuff and stick it in the mum's mailbox?

EDIT: We were best friends before we drunkenly fucked and feelings came about.