Re: "when people dial my cell phone number, it rings on her phone.
How can I fix that?"
Wondering if you inserted your SIM card in the other phone by mistake.
or
Maybe calls divert to your wife's phone if your iPhone is not available ?
If you can't activate your iPhone or iPad (Wi-Fi + Cellular) - Apple Support
or
If your iPhone is not working right, try re-starting it:
How to: Turn iPhone on or off – Apple Support
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Else: You might re-check the cellular settings on your iPhone:
View or change cellular data settings on iPhone – Apple Support
Maybe you want to use 5G:
Use 5G with your iPhone – Apple Support
Also:
Make calls using Wi-Fi on iPhone – Apple Support
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If problem still remains:
Get information about your iPhone – Apple Support
says:
Go to Settings > General > About.
You can check the info., listed is all correct for yourself and your iPhone.
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More support if needed:
You might want to reach out to the iPhone Support Team:
There's a "Get Support - start now" link (online chat, phone, eMail etc.)
at the bottom of their website (link below):
iPhone - Official Apple Support
All the best :-)