Mark said exactly what I was about to suggest

I agree but I would probably choose a watery blue.

Yes, but match it to the gray in your tile.

I like the blue. That is a lovely bathroom!!

rjd;

Agree that you have a beautiful room. I think paint above the wainscoting is a great idea. A couple of inspiration pics:

Good luck!

Nice bathroom! My choice would be a soft muted color, not more gray. But at least it's easy to change the paint if you do go gray, then later decide you'd like more color. Good luck!

I would definitely paint to give some contrast. Go subtle though, as others have suggested. And make sure you pull a color from your tiles.

What flooring did you use? Pros/cons? I'm looking for flooring for a white kitchen with light Quartz counters and I can't do hardwood. ;-)

Thanks everyone! We just moved into the house so o don't know what tile the previous owners used, sorry

I like the white. It works. I'd focus on other more problematic areas of home and save this if it bothers you down the road!

A pale grey will bring out the tones in the marble, so I think its a nice idea.