Hi Tuna. Sorry for what brought you here, but glad you found us.
I would suggest that (esp with your family background) you look into the options available to you locally to educate yourself about traits of codependency. AlAnon or CoDa could be good options for you for this, and for support regarding your partner / relationship, and how to make healthy boundaries and stick to them.
As you are finding out, you cannot change your partners drinking. Although I do wonder if you're actually buying her rationalisation and blaming that insinuate that you're the cause of it. You are not. Neither is her bereavement. Her drinking does nothing to change or solve either problem. Her drinking on these things is more likely dues to the fact that her alcoholic thinking has her label alcohol with the word 'Solution' rather than 'Problem'. It all gets a bit chicken and egg for us Alcoholics when we're active in our addiction. Lots of crazy-head thinking going going on. And while we can avoid the consequences of the chaos we're creating by bull-pooping and rationalising the longer we continue.
I would really strongly suggest that you post this dilemma of yours in the Friends and Family area as well. Those folk in there are likely to give you some pretty straight advice along with examples of their own experiences.
Friends and Family of Alcoholics - SoberRecovery : Alcoholism Drug Addiction Help and Information
Prayers and best wishes to you for a happy and secure future, and for your girlfriend to see the light and realise that there are better ways to live.
BB