hello alice and welcome,
maybe some recovering alcoholics will post to you with some insight. i hope so.
what i have read of the addiction is that the alcoholic functions pretty well as long as he keeps his blood alcohol level up. this might explain the hidden bottles, as he has to keep sipping through the day and night to achieve the required amount of alcohol to feel normal. it is when the BAC drops (for example, when an alcoholic is sleeping) that his behavior and personality can noticeably change, as it sends his body and brain into withdrawal. the addict wakes up feeling miserable and the using starts thereafter.
confronting him will be difficult and stressful for you. if you have not already confronted him, you might consider attending one al-anon meeting, asking if a longtime member of the group can offer phone support to you after your talk with your husband. you can also get some very good printed information at the meeting that will have great meaning for you right now.
you might also read the book "getting them sober" as well as getting some pamphlets from AA to offer your husband when you speak with him. he may throw them out, and be pretty nasty, but if you approach this with the attitude that it is a treatable affliction rather than shameful behavior, he might hear you. but maybe not right away. all addicts need to protect their compulsion to use. it is what the drug does to the brain.
it will be a long road and it is best to be educated and well-informed for your journey.
sending you all the best hope for your marriage and your happiness.