Setting aside the topic of wife training for a later post... let's talk about your first bike. Obviously it is a question that depends on a lot of factors... but I'm going to offer one general all-around option.
If you want a bike that is ultimately reliable... fun to ride... gets very good gas milage... and is easy to learn on.. I strongly recommend the Ninja 500.
Kawi has been making this bike since like 1988.. and I don't think its been changed at all since about 1993. There's a reason for that... its proven. There is no reason to change it. It does what it does extremely well.
It will put a smile on your face.
You won't have to spend all your time wrenching on it.
You will save $$$ in gas.
And no.. I don't care what anyone says... it is not to little for you.