How do I stop my sent and received text messages from automatically going to my wife's iPhone?

leitafromraleigh wrote:

go into your contact list... bring up your own contact. then message yourself from that. you will have to choose your phone number... from that point forward it will default to your phone!

Wrong.

Are you using the same Apple ID, or different Apple IDs?

If you're using the same Apple ID, that would likely be why messages (and other things) are being shared/synced between devices.

Stop sharing an Apple ID. You each need your own.

go into your contact list... bring up your own contact. then message yourself from that. you will have to choose your phone number... from that point forward it will default to your phone!