Weekend in a posh hotel for just the two of you could be fun - try Superbreaks.com and see what they can come up with.
Also, even if she isn't a jewellery wearer - who says she doesn't like it? I have a beautiful diamond and sapphire bracelet that hubby gave me a couple of Christmas's back and although it's rarely worn, it's often looked at and stroked.
It's the having, not the wearing!!