My Apple devices are sometimes asking for my husbands Apple ID and password

My husband and I have separate Apple IDs and Family Sharing. We have always had two different IDs except in the early early days of iTunes where you had to use one Apple ID for song purchases because there was no family sharing. Now both our devices periodically get confused and ask for the other persons Apple ID and password for updates on all kinds of apps.

If you are able to delete the app and reinstall it it will usually correct itself, but Apple Music remains messy and some apps make it complicated to reinstall if you don’t have a record of the original password or it doesn’t use one.

I have spent lots of time on the phone with Apple Care and no one can permanently fix this.

We would be willing to establish new Apple IDs but I don’t want to lose all the movies, tv shows, music and lifetime apps we have associated with our current IDs - and who can say that will even solve it