Hi there - 1 - I agree with the others. You are not contributing to her alcoholism. She is squarely responsible for that. 2 - I think that if she is always in some state of intoxication, you will not be able to reach her with any discussion of her issues, and that interaction will always always turn into a fight. 3 - in my humble opinion, I seriously doubt that you have a problem with alcohol. If you're literally having only one drink every evening, I see that more as a habit/routine, than run away drinking taking over your life, and/or causing intolerable consequences to you work/relationships/self.
I think your wife needs help. You need help to deal with this. Many talk about al-anon being wonderful for family members.
You may want to look up an addiction counselor as well. If your wife is drinking this much, she may need a medical detox.
Finally - my heart goes out to you.