Incoming calls to my wifes iPhone 6 are coming to my iPhone 6; how can I stop this?
Incoming calls to my wifes iPhone 6 are coming to my iPhone 6 and iPad ; how do i stop this?
iPhone 6, iOS 8.3
Go to Settings > FaceTime and turn "iPhone Cellular Calls" to off on each device.
The other option would be to use separate Apple IDs for you and your wife. That is now more flexible than it used to be with new Family Sharing features: https://www.apple.com/ios/whats-new/family-sharing/