how can my spouse and I use the same Apple ID ?

You should not. Each person should have their own Apple ID.

Sharing apple IDs will cause everything to be shared. This includes apps, and media, but also messages and phone calls, and photos and files and data. You do not want to share an Apple ID for regular use as everything will get mixed up.

If you need to share purchases from the iTunes and App stores, use Family Sharing.

No, don’t share the same ID!!! Instead each uses their own and you set up Family Share instead. https://www.apple.com/family-sharing/