The problem comes from the fact that you and your wife are using the same Apple ID. One of you will need to create a new apple id, and then use this on a phone. Once you've created the new Apple ID, on the phone that you will use this new id, go to Facetime and tap the apple id and select log out. Then turn off facetime (if is it hasnt turned off itself already) and then turn off imessage.
Restart the phone
Once the phone is running again, go to Facetime and turn it on. It should now ask you to log in to your apple id, if it happens to prompt for the old account, select other account, and submit your new Apple Id and password. If it doesnt prompt the old account, then just submit your new Apple Id and password.
It will activate using this new account. While this is activating, go to iMessage and turn on iMessage and it will also activate.
Note just becuase you use a different account for facetime and iMessage, does not mean you can't share apps with one apple id. You can you just need to go to the iTunes and Appstore settings, under setttings, and supply the original Apple ID inforamtion there.
Hope this helps!
my problem is as under will u help me out ?
my son in law from usa was using AT & T Iphone4 for last few years and after contract was over he gave it to me for use it in india, the phone was unlocked by at & t on request.
now, i use india sim card on the phone but when i try to hav facetime registration and activate it, it shows my son in laws old usa numbers, which i think will creat problem as i wish to use my india numbers when i get call from others on my face time.
hope u will be able to resolve the issue.
If you do what the one post said - change id - turn off imessage and sign out of facetime. Turn off phone and turn it back on, it works. I had the problem when I used my personal id on my work phone. I created a new icloud account on my work phone. Then on my personal iphone, I turned off imessage and facetime - turned off phone - turned it back on and logged in with personal icloud - work phone is now gone - no longer an option. Thank goodness. Not only did it ring my work phone even though it wasn't selected - I could only ANSWER it on my work phone.