To stop sharing photos between iPhones using the same Apple ID, turn off iCloud Photos in Settings on each device, going to Settings > [Your Name] > iCloud > Photos and toggling off "Sync this [Device]". For complete separation, consider creating separate Apple IDs and using Family Sharing for purchases, as sharing an ID syncs more than just photos (like messages, contacts, and call history).
How to stop sharing between devices with the same Apple ID?
Using the same Apple ID, Google account, or cloud storage service can make your husband's phone look linked to yours. Other things that can create the same effect include shared albums, file-sharing features, location sharing, or third-party apps that sync across devices.
To stop people from adding photos:
How to separate our Apple IDs and share things explicitly?
You can sign out of one of the phones and all iCloud syncing will stop and you'll lose access to photos/videos stored in iCloud.
Method 1: Unlinking from Settings on One iPhone
Open the Find My app, then tap Devices or Items. Tap the device or item that you want to remove, then swipe up on the handle. Tap Remove, Remove Item, or Remove This Device, then tap Remove to confirm.
On the Google Photos mobile app:
One possibility is that the iCloud Photo Library functions of your iPhone and iPad are both enabled. With this setup, all photos and videos are uploaded to iCloud Photos and therefore available on all devices with the same iCloud account.
What happens if you turn off iCloud Photos accidentally? Don't worry, everything will keep on iCloud eventually, you can download all the photos and videos from iCloud.com to the device that you might disable iCloud Photos. Thus, there is nothing to worry about.
Remove your associated iPhone or iPad
If you're unsure why your two phones are linked, simply go to Settings, select your Apple ID, scroll down to your linked device and select 'remove from account'.
iCloud Photos uses your iCloud storage to keep all of your photos and videos up to date across your devices. You can make more space in iCloud when you delete photos and videos that you no longer need from the Photos app on any of your devices.
You do not have to create a new ID. When you activate the new phone, just don't restore the backup of the iPad or don't download your purchased content to the device. You can go to Settings>iCloud>Photos>My Photo Stream>Off and any photos that you take with the phone will not transfer to the iPad.
Go to Settings > Accounts > iCloud. Under Photos, press Select to turn off iCloud Photos.
Manage, review, or leave your conversations & albums