Here's how my own drinking worked. I drank a lot at parties only in high school. When I went away to college (and nursing a broken heart at the same time) I met my first husband--a full-blown alcoholic at 18. He and I were drinking buddies through college. When I graduated, I started working and seldom drank--and my then-boyfriend's (future husband's) drinking really bothered me. He finally got sober in AA and 35 years later remains sober without a single slip. The whole time we were married I rarely drank.
When my first marriage ended, I met alcoholic number two--my own drinking ramped up, and again I had a drinking buddy. When he almost died from alcohol, I quit drinking to support his recovery. Eventually THAT marriage broke up due to his drinking.
When I left him, I started drinking a lot, especially at home. I got into a new relationship with someone who seldom drank, but at that point my drinking steadily escalated to the point where I could no longer quit or control it. I struggled for four years trying to "moderate" my drinking but could not. Through all of that time there was nothing external about my life that was bad. I had a good job, family, friends.
Nobody knows what makes some people become alcoholics and others not. My first husband was an alcoholic from almost his first drink. I, on the other hand, had red flags and a tendency toward it from the beginning, but it was later in life that I developed the obsession to drink. Recovery lifts the obsession.
If your husband is really working a good program, he may very well no longer have the obsession to drink. That's what recovery is intended to accomplish. But it doesn't mean the obsession is gone forever. If he drinks, or if he gets complacent about his program, then it can roar back to life. And often the post-relapse drinking is worse than it was before the alcoholic quit in the first place.
I know you have something of an aversion to AA, but if you were to go to a few meetings (not necessarily with him--you are welcome at any "open" meeting) and listen to others share about their experiences, you might understand it a little better. I don't think any non-alcoholic can TRULY understand, but you could get a lot closer to understanding.