Okay here a little background on the boyfriend...

There is no reason for him to be mad in my opinion. *I* was drunk, I don't have anything to do with him, I was just trying to get home safely, and I guess he's mad cause I'm drunk and she was with me. I wasn't driving around drunk with her so I wasn't endangering the girl.. and I'm clearly not a bad influence.. or else she would have been drunk too.

He is VERY insecure and has zero trust for her. He makes up scenarios in his mind and will find reasons daily to break up with her.