I cheated on my girlfriend anonymously for the last 6 months
Is there a reason you'd cheat on her for so long?
Yes, I met someone else on the internet who's more interesting
Cheating on your gf for 6 months is betrayal which is wrong. When you are unhappy in a relationship, end it first, before moving on.
What are you getting at? Do you think I've committed a crime?
Not a crime, but I'm sure your actions will hurt your girlfriend very much. You should come clean and tell her the truth about what you've done.