I know a few of my mothers friends who still have their wedding dresses hanging in their closets (gathering dust). They haven't worn them since their big day.
If you have not bought your dress yet you could always think about a 2 piece wedding outfit (a corset top and separate skirt). This way you can always wear either one by themselves again after the wedding. It would be quite nice to for example the corset top again and think back to memories of your wedding!
After my wedding I am thinking about helping out someone who can't afford a dress and gifting them mine. It is a tough question as so much there is a big emotional attachement to it.