The real problem?
Glad to hear you called the others and let them tell their side of the story, rather than doing something rash you would have regretted.
It sounds to me like your (now ex-) girlfriend's problem isn't going after other guys -- it's that she gets so drunk she doesn't know what the hell she's doing.
Hopefully your dropping her will be a wake-up call to quit binge-drinking or, if she needs help, join a 12-step program or something.
I had a substance problem myself in the early 90s and you wouldn't believe some of the incredibly risky, degrading, embarrassing things I did when I was high.
I can't believe how much kids drink these days -- by kids I mean folks in their teens and twenties. It's dangerous and self-destructive, not to mention how badly people embarrass themselves when they're fucked up. Kids might think it was less cool to get drooling drunk if they could see a video of the way they act in that condition.
When I was that age, a lot of people smoked weed, but we didn't generally drink ourselves blind. I think we considered alcohol our parents' generation's vice.