I didn't ruin any relationships, lose my job, or get into any legal troubles either. But as you mention,
400mL of vodka a day is slowing killing me and preventing me from reaching my full potential.
....
That.
Alcoholism had me stumbling at the starting gate; while everyone else was racing to reach their goals in life, I was making C's and D's in school, showing up late for work and missing job interviews. Alcohol replaced ambition with nonchalance and excuses to myself.
There are those who have a dramatic decline, the car chases, jail time, all that. But there are those of us who fail to notice that alcohol slowly steals away those things we simply cannot replace: our health and time.
I felt a huge amount of reluctance and shame in the face of sharing my fears about my alcoholism with my husband. But, of course, he already knew.
When I did finally bring it up, I felt like the weight of the world was lifted from my shoulders.
Not talking about it is keeping it a secret: secrets in relationships tend to create separation and distance. I would bring it up. You probably will be pleasantly surprised that she appreciates your honesty and is interested in being supportive.