Personally, I think drinking or getting high in the COMPANY of an alcoholic/addict is a form of enabling. It is one more "excuse" for his drinking.
If you are out with friends and want to have a drink or a smoke, that's different, to me.
Don't get me wrong--I don't think your drinking/smoking would be the REASON he drinks, but it just would make me uncomfortable. I was my second husband's drinking buddy up until he almost died from his drinking. At that point I stopped drinking in his presence, even when he went back to it. Just didn't feel right.
I also think it's considerate to avoid drinking around an alcoholic in early recovery, or any sober alcoholic who is made uncomfortable by it. My first husband eventually was secure enough in his sobriety he didn't mind if we were out and I had a drink. He didn't want me keeping it in the house, though, and I respected that. I feel the same way, after eight years sober. Don't want it in my house.