Most Helpful Guy
Don't do drugs and alcohol if you can't keep control of yourself. If you get blackout drunk there's no telling or remembering what you'll do, so good luck trying to keep a partner like that. He isn't overreacting in my opinion, I would probably break up with someone if we went to a party and she snorted coke, got blackout drunk, and grabbed all my friends junk. You didn't cheat, you were just wildly irresponsible in not keeping control.
Most Helpful Girl
Drink and drugs make anyone lose all sense of reality. That is why people use them. It was not a mistake. You chose to use drugs. Now you have learned a big lesson.
Yes, you did cheat, and deserve what you got.