I have to agree with formerdoormat. Based on your husband's description of his drinking habits (drinking daily, drinking when you are out, starting and stopping before lunch, straight vodka, etc), he has probably not really been sober for a while. It is very unlikely that he can just stop cold without any side effects. My mom's an A and she can seem quite sober, but I know that she has to drink round the clock to avoid getting sick.
This is not for you to feel shame around. It's not your's.
You didn't cause it, can't control it and can't cure it.
Do educate yourself and be prepared for a bumpy ride. Be careful that you don't just 'hear what you want to hear' and ignore your gut. Alcoholics can be very convincing and you already know that he can be very deceitful to cover his addiction. Your AH may really think that he wants to stop, but it is so much easier said than done. At the end of the day, he has to want to and he has to find his own way to do it.
Take care of yourself.