Her Ivory Dress + His White Shirt = ?

I'll be picking my dress up in 2 weeks, and so I think it is probably time to start thinking about what Suavocado will be wearing underneath that hot suit of his.

Here is a reminder of what my dress looks like:

If I pair up a white shirt under all of the suits with my pretty pretty dress am I going to be suffering from the dreaded "dirty dress" phenomenon? You know, the one that all mother's seem to believe in that dictates that ivory dresses will look scrungey next to a crisp white mens shirt.

Almost all of our groomsmen are church attenders that wear white shirts to church every week and so I know they already have a favorite white shirt hanging in their closet (hopefully right next to the black suit they will be wearing). Putting everyone in white shirts under their black suits would be free, and save me a lot of time (and money!) tracking down ivory shirts for everyone. Not to mention the fact that Mr. Av is insanely picky about dress shirts.

White shirt or Ivory shirt? What have you seen in the past?