I'm including some kids bows here because I really have no idea as to your wives skill level, draw length or strength.
The Matthews Genesis is the bow my club uses for teaching kids and adults.
It's only a 15-20 pound bow with zero let off. This sounds bad but with most higher poundage bows you are still holding 15-20 pounds at the back end. It's a great bow for developing good form.
http://www.genesisbow.com/products-page/bows/original-genesis-2/
The most important think with equipping someone new is to not over bow them (i.e. too much poundage). Modern compounds are very efficient and you don't need a lot of poundage to be effective, esp. if you are just looking to shoot for fun and do not need the KE required for hunting.
Darton makes a nice bow. My first compound and still my favorite bow was a Darton.
Darton Ranger X -
"The Ranger X is geared to take the young archer into the world of bowhunting. The Ranger has a draw weight range of 15 to 50 pounds, and comes with 9 draw length modules (17-28 inches). Finished in full camo, it will help blend young hunters into their surroundings. The Ranger bow is available as a complete package." MSRP $211
Darton DS-600
"The DS-600 is a great hunting bow. It’s the best value you will find in any bow if you’re looking for cutting edge technology at an entry level price. Its machined alloy riser and efficient E-Flex Limbs coupled with Darton’s DualSync cam system will get you started with shooting qualities you only find in top end bows. The DS-600 comes with a complete set of draw modules and an adjustable positive draw stop. These features give this bow the flexibility to grow with the archer or to be passed to other family members." MSRP $422
PSE Mini Burner 20# beginner compound MSRP $200
PSE Chaos AD 29#/75% let off entry level compound MSRP $300
PSE Chaos One 40#/75% let off MSRP $300
PSE Rally 50# and up /70% let off MSRP $300
Honestly there are so many good options out there now, it's hard to narrow it down.