This is basically where we started in the early 1980's.
We had no problem chartering a small monohull to gain experience. We now charter cats up to 50-feet.

You'll probably find that a small cat, under 40-feet, will be fairly easy to sail and easier to handle around a dock than a small monohull of about the same length.

Taking a course together would be fun, but your wife might get more out of taking a class by herself where she can't look to you as a crutch. My wife has had a couple of courses through Womenship to provide her more self-reliance. One I would highly recommend is one called "Sail Yourself Safely Home." It's focused on what she'd do if you because incapacitated.

There are also a lot of resources on line.

see: http://www.sailingvideos.com/product/1107/