First of all, it is a very useful app. I like the completeness, details and integration of the app the most.
Still, i see possibilities to improve the app.
You connected to AppleHealth, why not also the calendar app. I would like to see in my calendar when the dates were or are in the future.
The partner section would be more useful, if we could add more data. Like address (maybe with navigation link to maps), additional fotos, likes and dislikes, a quick overview when the last dates were. Maybe also a nickname/username for certain apps like instagram/Facebook. A url would be good too for having a link to a datingssite profile for example.
In the date section itself you can use custom place/current place, why not add home address, or partner address from the partner contact. Also i m missing a quick rating like 1-10.
that s all for now :)