If you completed a joint return- you can still NetFile your wife's return. For yours, you will need to click on Print and Mail. Then mail out your return to the nearest CRA office.
Even when you complete a joint/coupled return your returns get filed separately- you will see your name with NetFile beside it- and your spouse's name also with NetFile beside it. Therefore just as you did to NetFile yours you will go back to "File" and click on NetFile beside your wife's name.
