I think this is is something you could talk to your ABF about and find out what his thoughts are. Just be transparent and honest. His problem is his problem and his to own. But, if you want to be supportive and express that to him, find out from him what that would look like.
Everyone's recovery is different. Some can handle watching others drink and wouldn't want the other person to put themselves in a position of loss or sacrifice. While others may actually expect that level of support.
I found that when my XAH was trying his hand at recovery and going to AA, I would only drink when I was out with friends or if my XAH was traveling for work I might buy myself a bottle of wine and have a glass with dinner. But, it really seemed counterintuitive to me. I am not an alcoholic but I saw the damage my XAH's behavior had on our family so I really didn't drink much at all and I didn't feel that it was such a big loss.
Today, though, is a different story. I'm in a relationship with someone who has a healthy relationship with alcohol like myself and we often drink together. Usually just one after dinner or sometimes we split a bottle of wine if it's the weekend and we are home relaxing together. I couldn't tell you the last time I had more than that, though. I don't think either one of us have seen the other actually 'drunk' or unstable or slurring words or whatever. And, neither one of us will have more than 1 drink if we're out and going to be behind the wheel if we drink at all.
Anyway, it's all perspective. Hang in there and just keep the lines of communication open!