First let me say welcome to SR friend. You have come to the right place to learn about alcoholism and share with others who have or do walk in the same shoes you’re in. I’ll be honest, I get very mixed emotions about your situation. From the things you’ve observed it sounds like your GF does have a drinking problem. Drinking alone is a touchy one. I am not an alcoholic and used to drink alone on occasion, say a glass of wine. My GF on the other hand is an alcoholic and when she drinks alone it is more like a few bottles of wine and daily. The tolerance level you mentioned, however, is much more concerning. That is a LOT (10+glasses) to drink in a night and still be functional. The verbal abuse and attitude when you shine a spotlight on her drinking is also a strong indicator of the severity of her problem.
Let me play Devil’s advocate for a minute though…You mention a few times, “…after drinking like US,” and, “…will join US for after work drinks,” etc. You also mention partying and being hung over yourself. You have to ask yourself, if you really care about her and her sobriety, “Is this lifestyle conducive to helping or hurting the situation?” I think the answer is obvious. Easy before you get mad… I used to be quite a social drinker myself. I’m a trained chef, among other things, and I truly enjoy liquor, wine, and spirits, but when the love of my life confided to me that she had a drinking problem I simply said, “Well, WE don’t drink anymore.” Even though drinking isn’t a problem for me, I quit for her. Even if you don’t go that far, it seems the partying and other behavior may need some scrutiny in my opinion.
It also seems you’re also trying to decide if you should stay or go. That is the proverbial question that everyone, in sober or alcoholic relationships, asks at one point or another. All I can suggest concerning such an important matter is to set boundaries, identify some level of duress that you will not exceed, and most of all take care of YOU if you feel that your emotions, beliefs, values, identity, and health are being compromised. Keep reading and thinking and things will become more clear. Good luck.