How does a husband & wife split a joint apple ID ?

I have both my wife's (phone H) & my (phone J) iPhones linked to the same apple ID and

cell phone provider (i.e. Rogers) for over 10 years. After I upgraded to an iPhone 15 pro (17.4)

we started having problems wherein she would call/text and my name/ID would show on the receiving end.

How do we separate hers from mine while still retaining our contacts, "find my iPhone" functions etc.?

She has created her own apple ID but we are afraid of her signing out of my ID on her phone (H).

Will her signing out of my apple ID on her phone (H) affect my ID on phone (J) ?

Is there a way to link her new apple ID on her phone (H) to my old apple ID on my phone (J) once she

signs out of my ID ? Kindly advise & thanks for any input !