I would look for local oppertunities to get some sailing instriuction. It can only help you. To go out for that long means you'll run into most any type of situation possible and you'll need to be prepared. Confidence helps more than any other item you can take on a trip.
I would also suggest you do a quick one week skippered charter
to mentally get an idea of what you think you need to do to prepare for such a trip. That way there is no pressure on you or your wife for a week as you get used to it and get familiar with the operations. Add a little book study and maybe a class or two and you might actually be in a good position to start. But you clearly would be in better shape to really be honest about this with your wife and yourself.
BTW, you really don't want the bad experience.
BTW, you really don't want the bad experience. It can get far worse than you should ever know.
If you search around you can find some one that will turn you loose with very little training and skill. It might work but I really doubt it will be a positive experience.
I came to sailing with a power boating background and it helped a lot. Piloting, Navigation
, and other skills work the same no matter the boat. There is a lot more to it however and it helps to have a good start. Some local classes
on a small water
in a smaller boat that both you and your wife can participate in is worth your time and money
. My wife and I had a great time while we did that and I don't think she would enjoy sailing today if we had not done it that way. That alone was worth all the time and cost plus I learned a whole lot myself.