Splitting apple ids, migrating linked devices

Click here to see how to 'Create a new Apple ID' = create an Apple Account. --> How to create a new Apple ID - Apple Support

Merging Apple accounts (IDs) or transferring data is not officially supported. Read the links below for things you may need to do to transfer as much as is possible and to share some others.

Apps and media bought with one ID are permanently associated with that ID. Look into using Family Sharing to continue to be able to use items purchased with one Apple ID with other Apple IDs, and for some data sharing features.

- Family Sharing - What is Family Sharing? - Apple Support

- Set up Family Sharing - Set up Family Sharing - Apple Support

Share folders with iCloud Drive -->Share files and folders in iCloud Drive on iCloud.com - Apple Support

Read How to use Shared Albums in Photos on your iPhone, iPad, and Mac - Apple Support about how to share photos.

If you have signed into the first ID on a device then fortunately when you sign out of that ID, do not erase the device, then sign in with a different ID, it asks you in most cases if you wish to merge the data from the two IDs on your device. Say yes and later delete individual items from the other ID that you do not want. Note, in How to save apps and progress on one Appl… - Apple Community a Community Specialist says, "you will not be able to transfer the meta data from one Apple ID to another. Once you switch to another Apple ID the information associated with the old Apple ID will be gone except for physical content on the device like photos and videos." Also turn off storage optimization before doing this. With Optimize Storage, smaller, space-saving photos and videos are kept on your device while all of your original, full-resolution versions are stored in iCloud. To ensure you retain full quality photos, make sure photo optimization is turned off. Manage your photo and video storage - Apple Support

I believe health data is account specific so if that is critical for her, you may be the one who has to use a new account.

Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac --> Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac - Apple Support

If another Apple ID is signed in you may need to enter the password for that ID to sign out of that ID first.

Click on this link to learn how to 'Sign in with your Apple ID' --> Sign in with your Apple ID - Apple Support

Good decision to “split” AppleIDs - Sharing a common AppleID creates nothing but problems which only worsen as time progresses.

Unfortunately, the data “belongs” to - and will continue to belong to - the present AppleID.

So whoever has the “MOST” data generally keeps the current AppleID

Note: This AppleID CAN easily be changed later.

So the general process:

• Create the 2nd AppleID
• Change AppleID of current account if needed
• Designate either account as the Family Organizer
• 2nd AppleID is “invited” into Family and “joins”
• Share apple apps and services as appropriate.

See supporting info in links below:

How to create a new Apple ID - Apple Support

Change your Apple ID - Apple Support

Set up Family Sharing - Apple Support

It’s straightforward to change AppleIDs, so that’s NOT a compelling reason to not “split IDs.

There ARE some limits on AppleID “re-use” which can trip the unwary / unprepared … but we can help you steer around those issues.

You just have to think-thru your endstate and then take the steps in the necessary order to get there.

You will not be able to use your old email address with a new account. Apple doesn't say that officially anywhere but in the 18 years I have been on this forum many have commented about that. It is sounding like in the end it comes down to your wife keeping her health data or you keeping your account ID email address.