When people drink every day it is in my opinion "to feel good" and often they don't feel that great during the day so need that release but it can become like everything an addiction.

Lots of people i know it's industry related and stress but one of two glasses a night is where they leave it.

But putting in "ground rules" is like living with mum. Talking it through to understand each other's feelings about it may be better, if you can openly communicate. Not why do you, but so how's work, try to see if there is something there that he's actually unhappy about and offer support.

And maybe, create things a couple of times a week, like the pictures and a sport whereby there is no room to drink on those occasions instead of putting in a rule as a "reverse phsycology" type of thing where he is unaware that's what's happening. And have some fun together see where that leads.