Hi, ess bee, welcome to the forums!
Some SIM cards carry the proper settings and will apply them on their own; that sounds like the case with your wife's SIM. Others do not carry the ability to apply the settings fully on their own.
If you can find the APNs you need for the specific carrier you're trying to use, then go to:
Settings > Wireless & networks > Mobile networks > Access point names > tap Menu button > New APN
Fill in all of the required fields for your carrier and then tap Menu and Save. Select the newly created APN and you should be good to go. Some carriers have more than one APN, so make sure you look thoroughly to make sure you have all settings needed.
Good luck!