My best friend doesn't want anything to do with me anymore?

About a week ago i got drunk with a few other friends (stupid mistake) and i starts texting my best friends girl friend and start flirting and she tells her boyfriend, well he is already pissed off about that but the next day she dumps him and he thinks that it is my fault that she dumped him and i tried explaining to him that the flirting was a mistake cus i was under the influence but he just wont listen to me and said that i'm dead to him and i feel really bad and i am upset about all of this and i still wanna be friends with him. What do i do??