So you, a cheater, are asking if your girlfriends actions were too violent? Sounds like you got what you deserved for your actions. She may have physically stung you with a smackbut you stabbed her emotionally with cheating.
She's so awful for being angry at you! Cheating is totally fine. I don't understand why she was angry at all. I mean yeah she hurt you but thats so unnecessary because deep dicking another girl totally doesn't sting her. I'm so sorry you had to encounter such an irrational woman. Fuck having crazy girlfriends am I right? She sounds batshit insane towards such a good boyfriend.