Hey jjwinters. You came to the right place. So glad you posted here.
I was A LOT like your girlfriend before I stopped drinking. My boyfriend essentially threatened to leave the relationship and so I sought out help.
The thing with addicts and alcoholics is that THEY are the only ones who can stop the behavior. You definitely don't want to accommodate or make the behavior more likely to happen, but the "tough love" approach won't necessarily help either.
My suggestion would be to gently tell your girlfriend that you are worried about her and the success of the relationship if she continues to drink. She may become extremely defensive- prepare for this. Tell her that you are not sure if you are able to continue the relationship if she drinks.
If she continues to drink and does not stop, tell her that you will only go on dates with her that do not involve alcohol. Again, this may not work, as she may try to get that bottle of wine on the way home, or show up to dates drunk.
I would also refer your girlfriend to this site to see that there are MANY more like her, and there is a way out.
At the end of the day, this is all you can do. SHE has to decide that it's what she wants. If she decides that her drinking is more important than the relationship, you guys may end up breaking up.
I know this is really hard to hear, but it is inevitable. Either she will stop drinking, you guys will break up, or you will continue to suffer in an unhappy relationship and it will take a toll on your own emotional health and you will come to resent her.
This same pattern happened with my parents, me and my boyfriend, and COUNTLESS other alcoholics.
I wish you the best of luck. I know that isn't easy to hear, but if she isn't willing to give up drinking, the relationship may have to end.