People saying that the OP shouldn't have mentioned it seem to be assuming that she just threw it in there as a bit of juicy gossip. The discussion was about alcohol (mis)use, so she gave relevant information that could have proved interesting/helpful, depending on the exact nature of the conversation, and which she confirms that her husband would be happy to be shared.
If people were having a discussion and expressing concerns about obesity, and you had previously been morbidly obese but had since lost 10 stone, would you think that, now you've been very slim for ten years, your personal experience would have no relevance to the conversation and you should therefore not mention it?
I don't think you could blame her for being somewhat taken aback if she wasn't certain (as many people wouldn't be) what 'recovering' alcoholic meant, but as soon as she was told that he hadn't touched a drop for 10 years, that's the point after which you would expect people to understand what the simple language means.
Does this woman not realise that, every time she travels by bus, taxi, train or plane, there's a 95+% chance that the driver/pilot has been drinking.... sometime in the previous week or so, that is. If that fact would upset her then it stands to reason that OP's husband should be among the tiny minority of people whom she WOULD trust, not having drunk alcohol for a whole decade.
Would she judge me if she knew that I go out in public daily, completely naked.... beneath my clothes? Or that I lift items from shops many times a week and simply walk out with them.... having handed over some money just before? If not, whatever sane reason could you give for objecting to a driver who had been drinking....over ten years ago?
Supposing OP's husband was 36, would this woman also feel bitterly betrayed not to have been notified that, twenty years previously, if he had decided to drive a car, he would have been doing so illegally and most probably dangerously? That would make as much sense - i.e. none whatsoever.