It's all about trust. IMO that's what destroys a marriage where 1 partner is an alcoholic. Your wife needs 1 on 1 counselling with an addiction counsellor. Mention it to the marriage counsellor - I know that if my husband told me I needed help I'd freak but if I heard it from an objective third party I'd consider it.
Believe me your wife doesn't want you to go back to drinking. She's protecting herself. I realize you're going through a hard time and you feel your wife should be supporting you - she needs to see it to believe it. I've been let down so many times that I don't believe it anymore. If he does it great but I don't count on that and I don't need that. He needs that.