My heart goes out to you. Dealing with addiction can be a lonely, isolating place, particularly in a marriage.
The excess drinking is a symptom of something. Whatever it is, it needs to be dealt with - whether it is deep-seated insecurities, childhood trauma, depression, an incredibly demanding job, etc.
If you haven't already, I would sit down with your wife somewhere calm (NOT after an incident) and explain a) you love her b) you're worried about her and c) you want to help her and try and discover the demons driving her to alcohol. Tell her how much sadness she is causing and the effect it has on you. Be prepared for a total lack of owning up to the issue.
I would also call the AA hotline and have a chat with a volunteer. They will give advice on how to support her and also tips on how to support yourself.
I would also try marriage counselling. PM me if you would like a recommendation. We turned to someone who made a difference to our marriage (although it's been bloody hard work and taken far more perseverance than I ever thought possible).
At the end of last year, Susannah Constantine wrote and spoke movingly about having been a functioning alcoholic for decades. It's worth a read.
You have my sympathy and best wishes. Just know that you aren't alone.