Just a note: While I think Magic: the Gathering is one of the best 2-player games ever created, my suggestions are based on keeping things simple for your wife. Carcassonne I think is great because it has the strategy that keeps you interested, while having a great theme - you're placing tiles that build cities, roads, farms and cloisters - that should keep your wife entertained.
Carcassonne is one of the good entry points to Eurogames, as is Ticket To Ride: Europe and Settlers of Catan (the latter is 3+ players, though). Thurn und Taxis is also a worthy contender.
Cheers!