I think it's Ok to let you husband to see your wedding gown before the wedding. I don't believe that would brought any bad luck. How can a good marriage ruined by this kind of tiny thing? But if you do care about giving a surprise for your husband when you show up, then you'd better not show him the gown beforehand.

Actually, if I am gonna go shopping for the gown, I will definetly like to go with my husband. I only worry about that he won't be willing to go with me.