It's gorgeous, and such a great romantic story! I'd flip it. An East West setting would proportionally work well on your hand. Halos are fine but there is a lot of fuss with them checking prongs etc. I'd do a champagne halo. Potentially, less expensive and a fun casual yrt romantic look. The tawny taupe would look pretty with the soft blue of your stone.
@Onebagtoomany , I agree with @saligator; I would consider east west too!
also look to Verdura Belperron for inspiration
Leen Hyne, or briony Raymond for modern settings
IMO adding diamonds and WG makes it dressier and more classic. How about yellow gold for a casual look
or consider a pendant or as the anchor to a bracelet