Getting my wifes text messages on my phone

This happens when you both use the same Apple ID for iMessage. To fix this you have two choices:

1. On one of the phones go to Settings>Messages>Send & Receive, tap the ID, sign out, then sign back in with a different ID. Note: you can still share the same ID for purchasing in Settings>iTunes & App Stores; or
2. On both phones go to Settings>Messages>Send & Receive and uncheck the email address(es) shown under "You can be reached by iMessage at". Also uncheck anyone else's phone number, if present.

You are probably sharing an apple id in settings messages.

sign in with separate ID's

Taht should do it.