Start with the lessons, and something simple (sunfish, etc.) that you can throw on the car and use at your lake. They're cheap, easily bought and sold used, so you won't get stuck. You will get wet sailing it, but wth it is summer now.
The sailing school usually can put you in touch with whatever local resources there are, and if there are clubs in your area that have any kind of races, they always need crew and you can usually hitch a ride.
Of course sailing on a sunfish and sailing on a bigger drier boat which has a HEAD on it are very different things, especially for the wife. Whether she'll like it, you won't know unless you take her for some lessons on a bigger boat, maybe a long weekend at a destination where you can do that. If that works...ask what they have that's a bit longer, get her exposed to it in a couple of different places and she if she likes it.
Some folks will take a couple of classes and work up to a week-long "bareboat" class, then just charter a boat for a week twice a year. That's one way to sail without having to maintain a boat--and find out strange things like, your wife might say she prefers a BIGGER boat. With a nicer galley and head.
If she doesn't, then you have to decide: The wife? Or sailing? It's a common problem.