The dress from my first wedding I donated without a backward glance. It was a suit rather than a big gown, and that may have increased its donate-ability.
For my second wedding, I wore separates that are hanging in my regular closet, mixed in with my other clothes.
If you're not sentimentally attached, I believe you should not feel badly about donating it. It's a dress, it's not your marriage or even the memory of your wedding.
On the other hand, I do have my grandmother's wedding dress from the 1920s. It's simple and doesn't take up much space (not a huge beaded lace affair) and I have the photo of her wearing it, so that feels special to me.
If you decide you don't need to keep it, is there a place near you where you can donate items like that for low-income girls? The school district I worked in used to collect fancy wear every year for the prom. People would donate their bridesmaids dresses, evening bags, shoes, etc. and the girls would come and "shop" the donations.
Maybe it would feel better if you knew it went to a good cause.
