As a photographer who has photographed a number of weddings over 5 years, I am choosing to write about a topic that I feel isn't discussed enough: the dress... before and during the wedding.
It is so exciting for you as a bride to put on that dress the day of the wedding. The feel of the fabric, the weight, the meaning. All of it culminates with the meaning of the day and specialness of this particular dress...that you may never wear again. It is so clean, so crisp, so white. Everyone (bridesmaids, mother, mother-in-law, groom) gasps and proclaims it beautiful! And it is.
However, as you move around at some point, you must realize: it will get stepped on, touched, messed up. During bridal party and family photos, undoubtedly, someone will step on the dress, or the ground may be moist. The dress will get a smudge of dirt. My recommendation would be to discuss this with the wedding party ahead of time and tell them you do not want to hear about a smudge. Ignore it and stay in the joy of the day.
Even if it stays clean, depending on the design/material of the dress, it may attract bugs between the layers. Again, your bridesmaids or well-meaning relatives/friends may wish to stop and remove them. This can take time and thus equals time lost during your portraits. My suggestion would be to tell your bridal party to leave it unless it is a larger insect or blatantly obvious like a large twig. Little bugs honestly won't be visible in the end photos.
And even if something gets spilled on the dress, there are ways to avoid it in photos: posing the stain away from the camera, blocking it with another person, and editing.
Hopefully this has prepared you to go into your wedding prepared for the beautiful dress to become soiled. It doesn't have to be a source of drama. Let your people know that you don't wish it to be an issue but rather to leave it be and just enjoy the day.