Q: Text message parallel to my wife's iphone

Are you sharing the same iCloud account?

That is your problem. You are sharing the same iMessage email address used for iOS devices to send messages too. Go to settings=>messages=>receive at. You can change the iMessage apple I'd here to another email so when people iMessage to that email, you won't receive them both. This would only happen when another iOS device sends a message to that email address or replies to the email. Or you can setup a separate iCloud and now you'll have you own photostream, contacts, iCloud email, iMessage email, ect.

Worked for me, brilliant!!