hi i know this is a little lame
Actually mate it's very lame. You have also previously started a thread about this: polishforums.com/relationships-marriage-36/this-cheeky-bastard-flirting-gf-63457/
Although there is no actual evidence that your gf is cheating on you, I wouldn't be surprised if she is.
She's probably looking for a better bf who isn't so jealous and doesn't spy on her conversations and post them all over the internet...
You need to grow. If you're not happy then finish your relationship with her; while the choice is still yours to make.
Good luck! :)