Suddenly getting spouses texts and phone calls

You need to stop sharing an Apple ID. One of you needs to create a new one. Then, you can use Family Sharing to share content.

Here is the whole procedure:

• If you don’t have a recent backup, create one on your computer or in iCloud (just for security, you probably won’t need it)→How to back up your iPhone, iPad, and iPod touch - Apple Support
• Go to Settings/[apple ID name] and tap Sign Out
• If you sync to iCloud you will be asked if you want to keep the content that syncs; say yes
• Tap to create a new Apple ID
• If you sync to iCloud, go to Settings/Apple ID name]/iCloud and turn on the switches for items you want to sync.
• Log in to the same email accounts you had on the shared Apple ID if they have logged out (they probably did not, unless one of them was an iCloud email address)

Contacts, Calendars, Notes, and Reminders sync to email accounts, so if you are logged in you will still have all of them. You will also still have all photos.

Next, decide who will be the family “organizer” and have that person set up Family Sharing→Set up Family Sharing - Apple Support

You can share all previous and future purchases; here is more information on that→Share with your family - Apple Support

(credit to Lawrence Finch)

Make sure that each family member has a unique Apple ID as suggested in this support article --> Make sure that each family member has a unique Apple ID - Apple Support

This support article tells you how to create a new, non-child Apple ID = create an Apple Account. --> How to create a new Apple ID - Apple Support

Apple has no formal account merging or transferring process. The things below will help you in doing ongoing or one-time transfer of as much as possible from one account to the other, but some things can never be transferred (namely purchases), only shared.

You can use various iCloud sharing features for some ongoing data sharing.

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.

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 - Share with your family - Apple Support

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

The next section may sound tricky but it lets you merge some things on a device where you have already signed in with an old account but want to use a new account and incorporate data that is already on the device from the old account. Incidentally, the data will then propagate to other devices using iCloud with that new ID. (I haven't tried this with a computer but it may also work with a computer account signed into an old ID.)

If you have signed into the first ID on a device then fortunately when you sign out of that ID it asks you if you wish to retain the data from the old ID on your device (toggle the ones you want to on). If you keep data on the device then when you sign in with the other ID it will merge this data with the account signing into the device. You can later delete individual items from the old ID that you do not want. Similar information can be found in this post I have 2 apple IDs i want to merge them h… - Apple Community Note that only content physically present on the device like contacts, photos and videos will be retained. Meta data such as a game play scores that are tied to a specific ID or are only on a vendor's database remotely will not be retained. 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. Make sure photo optimization is turned off so the full quality versions from the old account are actually on the device before merging the content into your new account. Manage your photo storage - Apple Support You can turn optimization back on again once you are fully using your new ID on the device.

Even though apps may remain on a device and may work for a while, you will not be able to update them or redownload them unless you buy them again with this ID or download them with this ID using Family Sharing.

Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac --> Sign out of iCloud on your iPhone, iPad, 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' --> https://support.apple.com/HT204053

The question instead is why it wasn't happening before when it should have. ;-)