Only when he's drunk: does it make a difference?

I'm lost. I'm confused. And I'm so fucking hurt.

Two nights ago my SO and I were relaxing a little bit with a few drinks. Everything was going great, we were laughing, talking about everything in our lives' and just enjoying each other's company thoroughly. He decided to have more than me which made sense, I'm 5'2 130 lbs and he's 6 foot 270 lbs and he always has to drink more than me to be feeling good. I remember the night perfectly. Just got a little toasty to wash out the stresses of the week. Well suddenly, this man that I love so much goes down some dark road. I had just returned from the bathroom and I am now being called a cunt, a bitch. I knew he was definitely drunk but he's making no sense saying "everything is permitted" over and over again. Mind you, I literally don't know where the snap happened. I am totally with it and now I'm just confused. He continues to yell, I tell him to stop calling me those names and now I find his hands around my throat. After a struggle he releases, mad now that I had kicked him in the stomach which is where I get punched in the gut twice by him. Now I'm scared. I try to get away and he bear hugs me from behind telling me "you're not going anywhere" I'm pleading with him to let me go and we can stop this here. He carries me to the bedroom and slams me on the bed. He's yelling and slurring. Continuing the name calling. I crawl onto the floor with a pillow and blanket with my back against the wall so I can see everything. I don't want to sleep with him but he has the door blocked off.. he rips the blanket off of me, opens all of the windows, turns on the AC and says he hopes I freeze all night. I'm starting to cry, I'm just stunned and fucking frightened. The crying induced laughter from him. Full on fucking hysterical laughter. I felt so alone. The name calling continued all night, he refused to let me leave the bedroom, slept in front of the door with all of the blankets so I couldn't get out or have one and if I didn't get on the bed he continued to crawl up to me whispering "you fucking cunt" in my ear. Ladies, I'm faithful, I try to always do something nice for him, let him know he's loved. We have always gotten along so well, understood each other and just loved each other so much. I don't get it, I didn't even say anything that set him off. All night he switched from being so unbelievably aggressive to crying saying "I can't believe you're going to leave me" when I never said anything of the sort. I'm not an idiot and I know this isn't acceptable. I haven't even been able to let him touch me since. I can't even look at him. I have bruises and my neck is so sore where he choked me. He cried to no end when I told him what happened yesterday morning. He can't believe it and can't remember a thing. I can't forgive him. He is begging me. Is it wrong of me to not want to offer that forgiveness, at least not yet? That was the most scared I had been in my entire life. He acted up one other time while drinking but nothing to this extent. Ugh I hate this. Please give me insight. I'm so confused here. Thank you in advance.