Lots of history in a relatively small space of time. First experience was that he went on a works night out and I offered to pick him up as he was coming back to my house afterwards and I thought I'd save him the taxi fare. This was very early on in our relationship, like 4 months in. It was the first time I'd seen him really, really drunk. He got in the car and absolutely stunk of alcohol. Almost immediately he started saying "you've had enough of me, I can tell. you don't like me anymore. you may as well drop me off here because I can tell you hate me" etc etc he went on and on. When we got back to my house he started saying "why do you even want to be with me anyway? you don't like me. It doesn't matter, it's not a big deal if we split, our relationship is meaningless anyway" etc etc. He was getting mean in the things he was saying but was no aggressive. I was devastated and went to bed thinking he was dumping me. Next morning - totally oblivious to what he'd said everything was fine and he apologised for being a twat and said he gets down and paranoid sometimes when he's drunk.
That Christmas I agreed to pick him up from another night out - this time he got in the car, started on me again but was actually quite nasty about it, started raising his voice at me and saying horrible things. After this incident I told him in future he'd be getting a taxi home.
Well time has gone on and there are too many examples of nasty aggressive behaviour when drunk to mention. A few examples of really bad incidences where he's come home and shouted at me, made me cry, said horrible things and just been a complete arsehole and a very recent example where he just went crazy and started swearing at me, jumping around, laying on top of me in bed because he said I took too much of his side up and he had nowhere else to sleep (!!) and suddenly screaming and shouting that I'd punched him in the face. I didn't obviously, turned out it was supposed to be an impression of me although I've never accussed him of hitting me, I just get a bit jumpy when he's drunk, aggressive and flinging his arms around! More in fear of being accidently hit in the process.
Anyway after the most recent example I said I couldn't cope with it anymore, I was becomming frightened of him and he'd said so many horrible things whilst drunk that I'm actually starting to become quite bitter and angry about it. We talked it through and he promised it would stop and never happen again.
Now, he's been invited on a works night out this coming Friday and has agreed to go. He wants me to pick him up as a taxi would cost us a fortune and he says he'll be coming home around 11.30 - midnight. I'm always wide awake at this time so it's not that it's particulary late for me. But I'm scared of how he'll be when he's drunk 
I told him this and he promised he won't start. I know this has to be a very last chance and I'm scared he will mess it up