well, if you attended AA, then you will know that the cornerstone of recovery is honesty.
why don't you try being honest with your family?
i would imagine that if the DUI was a one-off incident, everyone would understand if two years later you want to be a casual drinker. most adults of western society are casual drinkers and even casual drinkers get themselves into trouble when they drink too much.
all that said, i wouldn't want to drink on my wedding day. i would want to be sober, fresh and at my best.
you don't need alcohol to celebrate, you know. you can have a good time without it. is it worth upsetting your parents over a drink of champagne? i think not, after the worry that they have been through.
why oh why is it such a big deal for you to have a few drinks at your wedding?
to someone who isn't troubled with drink, it's like saying "oh i wish i could have baked mushrooms at my wedding but i can't."
why not tell your parents you have been taking a casual drink and then have sparkling cider for your glass at the toast?
i imagine you will have a better day (and first evening with your husband) if you skip the drink.
just my two cents.
naive