My partner and I have tried a few couple apps over the years.
It never really worked out. Every time, we ended up with our memories scattered across random apps that we eventually abandoned. Usually it was because the app got bloated with weird features, the price suddenly doubled, or we just got tired of logging in.
What bothered me most was realizing that all our notes and photos were sitting on some stranger's server, tied to an account we had to pay a monthly subscription to keep. If you stop paying, or if the company goes out of business, your own memories are essentially held hostage.
I didn't want to rent our relationship history from an app. So I built Warmth to give it a try myself.
In Warmth, your entries stay locally on your phone and sync to your partner's device through a shared, private iCloud space. It's shared between the two of you, but private from everyone else (including me). Even if you never pay for the app, your memories are kept and they keep syncing between you two.
If you also hate subscription-heavy couple apps and just want a quiet space for two people, it's on the App Store.
I still need to add a proper export button so people can easily dump everything into a folder anytime.