Chronic alcoholism does have disastrous consequences on potency. I've also read that impotence caused by alcoholism is irreversible. You have perfectly normal expectations as a woman of your partner. However, your partner is an alcoholic, so you should lower your expectations. As the disease progresses, you should expect less, not only when it comes to intimacy. The promises are broken more often, you cannot rely on him, you can actually expect that he will not be there for you when you need him most.
That's how alcoholism works, sorry.