First of all, congratulations! You don't mention which airline you're flying or the routes you're taking. If it's a Hawaii route many folks are there for a honeymoon so it's not a big deal to the airline. Why not use your miles to upgrade your flights yourself? That will impress your wife-to-be.

Also, you could always ask your guests to purchase your honeymoon instead of the toaster/blender that you really don't want/need. There are several companies that do that. See knot.com If you're using a travel agent they could also try and get you an upgrade.

Finally, don't have any expectations and then you won't be disappointed.