I think a taupe-like wall color would coordinate better with the tiles. Look at BM Litchfield Gray and see how it looks next to the shower. You can try going darker, but I think a warmer color is going to work better.

Ah never thought of taupy grey .Thnk's! I'll def check the BM out..

The tiles are dark looking in the photo..if you paint darker you may end up with a cave sort of feel..I would try floor to ceiling drapes on each side where's the tile and the paint meet...an elegant narrow fabric panel that matches the wall will break up the noticeable color difference and at the same time spotlight the beautiful tiles..the existing shower rod can support a shower liner that will hide behind the drape when not in use

To tie in the color change perhaps a decor piece over the toilet that ties back to the tile color..eg.metal sculpture..photo collection...perhaps even a "tiny tile" mosaic stripe border just above the sink height across the wall

I think espresso/darker cabinets would work best! Love this bathroom.