Carrie realizes part of the downfall of her wedding was the wedding itself. Sure, Miranda's comment to Mr. Big didn't help, but it wouldn't have had such a major impact on him if he weren't already so close to the edge. I mean, how many couples get heckled at least a little about "giving up their freedom" or some other such nonsense. Actually, that's what bachelor and bachelorette parties are all about - the "last hurrah."
Ladies (and some guys, too), don't forget the central reason for having a wedding - and it's not the party. A wedding is about two people publicly celebrating the fact that they have decided to join their lives. Don't let the planning and the flowers and the linens and the lighting and the music and the dress and all the rest of it come between the two of you as a couple. Keep communicating; keep the marriage and the fact that there is a deeply profound reason for the wedding celebration at the forefront of your minds always. And then, plan a fabulous wedding that truly celebrates the two of you as a couple!