you've been apart for 5 months. It's not your business anymore. Ignore her. Move on. The fact you have access to all those accounts is ******** creepy. The fact that you think harassing these accounts could actually be considered revenge is a little retarded.
If she cheated on you once, and is trying to cheat on the new guy, what makes you think she's not going to do it again?
They'll both learn a lesson. He'll learn to never trust a cheater.
And maybe she'll learn to stop being a lying slut, eventually. The end.
Harassing a bunch of shitty accounts which, did I forget to mention, is really ******** creepy, isn't going to help anyone.