The problem with a Dslr is that whenever you ask someone else to use it, you always end up with blurred out of focus shots, so when you look back at your photos it will be like your wife went on the honeymoon on her own!(as you end taking all the photos) Just take a good quality compact that can shoot RAW, there'll be plenty of other holidays for the whole camera kit but only one honeymoon.
Very true, but I prepare for those situations. It doesn't take me long to configure my DSLR to something like a point and shoot (smaller aperture, auto ISO, auto focus points, etc.).
For cameras that have it (Rebels do, don't know about higher steps), just turn the dial to the "green square" (or equiv for Nikon/Sony), that forces the camera into as close to P&S as you can get with no effect on your normal settings.
For my honeymoon, most of my shots were either my P&S or a waterproof P&S (a MUST if you're going anywhere wet, I got lots of good shots with my waterproof P&S that I never would have been able to get otherwise). I did have a Rebel with me and a slightly better then kit lens zoom that performed perfectly well. Carrying mostly a P&S let me capture all the moments I wanted, without letting the photography rule me during our trip.
I had a DSLR and did use it, but not that much, I focused on my new wife and enjoying myself.
Focus on what's important IMHO. This is a trip of a lifetime, make sure you enjoy it to it's fullest.