In all honesty, being car free really is not feasable for a large amount of the population. Our cities, countryside, and towns just are not built for it. Don't feel bad about failing at something like that.
Moving like that really is a huge change. I know the feeling. I moved to DC from NC right after college to live close to my wife's family, and I was terribly miserable and depressed and it really took a long time to make friends. Roody is right about it being tough to make friends other than work or school. I wish I had good advice but the best I can think of is for both you and your wife to start making friends together. My wife and I moved to SF a few years ago and other than one guy, all my friends are husbands of her friends. I'm not so sure its not pretty similar for a lot of married couples who move to new places.
As far as being car free, don't worry about it. It is not like it is the "right" thing to do or anything. If anything it is an eccentricity.