"I HATE the Dress My Future Mother-in-Law Bought for Our Wedding! Can I Veto It?" (I Say, Calm Down!)

Writes Save the Date reader Elliana:

So our wedding colors are black, gray, and silver. I picked gray suits for the guys and black dresses for my bridesmaids—then my future mother-in-law announced that she ONLY wants to wear black. I hinted that I'd rather not have her in the same color as my 'maids, and she dropped it.

I went shopping with my mother a little bit later and she picked a dark purple dress that I thought would look great with our wedding colors. I emailed a photo of the dress to my future mother-in-law and suggested that she pick a dress that would sort of match, maybe dark purple, dark cranberry or gray. I also sent links to nine dresses in these colors from Nordstrom, which she had previously told me is the ONLY place she'd shop. I heard nothing.

A few days later she called my fiance and says she bought a dress but she's really, really worried I'm not going to like it. However, she says she'll be DEVASTATED if I say she can't wear it. When I got home from work, my fiance told me about it and said he thinks I'm going to have to OK the dress, since she seems so dead-set on wearing it.

Then she emails us a picture of the dress, which is BRIGHT red.

I tried to stay calm, but eventually I started to panic. She's going to stand out FAR too much in our photos. So how do I tell her she CANNOT wear the dress when she told my fiance she'll be super-upset if I say no? I don't want to upset her, but I also want everyone to look good together.

I checked and the dress does come in black, which isn't ideal, but maybe a cute silver wrap would set her apart from the bridesmaids? I don't know what to do! Help!