How is he reacting to the situation?
Remorse, disgust, minimising it, blaming her??
If he doesn't usually drink and he was emotionally fired up about retirement and off his face then perhaps it was a one off occasion acting completely out of character. If so he is likely disgusted with himself and not knowing what to do to put it right, and feeling pretty foolish.
What do you want him to do now?
Never drink again? Apologise? Marriage counselling? Leave the house while you think about it?
He can't un-do it. No matter how much you both might wish that were possible. Although this is not faithful behaviour he presumably did not set out for this to happen and its from what you say it would unlikely have happened if he'd not been drinking.
At the moment there is a wedge driven between you. I suppose you have to decide if you want to extract it and work together to heal the relationship, or if you want to bash it in further. If you want to go for reconciliation then the sooner you start that the easier it's likely to be.
I feel for you though. Not a nice discovery to make.
Xx