So how...err...'marvellous' is she?
thin white gold band with a sapphire between two diamonds
I'd've gone with a titanium band. Everyone has Gold and as symbolic as the circular nature of the ring is, nothing says "I wanna spend the rest of my life with you" like a chunk of metal that can withstand a point-blank blast from a .44 Magnum. Also, titanium has a somewhat unique and long-lasting shine whilst giving a good contrast the blues of the sapphire.
And I'm afraid I've also got to criticize your response to the gloves. The ideal answer woulda been something like "Pfff. Gloves? Try this
instead" only less....err....an0n-ish.
Other than that though, as far as proposals go that's pretty damn good, if not somewhat cliched.