If you're that close with someone, the best thing to do is to use syncthing to synchronise your Photos folder. Every photo you take ends in that folder, is synchronized to your partner's Photos folder, and they will see it as if they took it.
Add another syncthing to your computer and you can comfortably browse your photos there. Reorganize in albums from your computer if you want, and you will see the albums on the phone.
All of this is just using the base syncthing and doesn't require any technical skills. Backing up in the cloud needs more time and expertise, but after having done it myself and realizing I don't actually need it (a simple backup is enough, I don't need a web interface to do what I can do faster and more easily from a desktop app) and I can have encrypted backups instead. Bonus: if you're both on the same wifi the sharing is quasi-instantaneous and doesn't waste energy sending to a faraway server first