Manmust, I've started to respond to your initial post about 5 times and then deleted my response because everything you have described hits so close to the core. Three years ago, I was behaving exactly like your girlfriend, and my husband was doing all of the things that you've done to contain the situation (i.e., me). The one difference was that I realised I had a serious problem with alcohol and eventually came to understand that I am an alcoholic. After 2 years sober, I relapsed and my husband is once again afraid to let me go to the grocery store alone for fear I will be gone 10 minutes longer than expected having downed an entire bottle of wine in that extra time. Sound familiar?
Your girlfriend is almost certainly an alcoholic. Others are giving you excellent advice about attending Al-Anon and participating in the Friends and Family section of SR. I just wanted to chime in and give you my perspective on your girlfriend's behaviour as one who was/is her, in the relevant ways. Best of luck to you in however you choose to move forward.