A lot of couples who are my friends have the same problem when they are drunk.
One time my friend and his gf got into an argument at a party where they were both drunk. He got upset and walked out the door and she followed after him. He tossed his beer bottle up in the air and it came down and hit her right in the face. Everyone thought he had hit her or somethin.
They just dont drink together. At least one person's there to be the DD.