Jesse Petersen - Flip This Zombie (Living with the Dead, Book 2)

The Zombie Apocalypse has been good to Sarah and David. Their marriage is better than ever. They communicate well, share responsibilities, and now, they're starting a business. ZombieBusters-for all your zombie extermination needs.
There are lots of zombies and that means lots of customers…Except one of them doesn't want the zombies dead, he wants them alive and ready for experimentation. Mad scientists make for difficult clients and this time, Sarah and David might have bitten off more than they can chew.