Many couples plan meals in their chat: a link here, "can you get eggs?" there. It works until you need to find something.
The problems
- Recipes and lists scroll away under other messages
- Nobody knows what's already been bought
- There's no single view of the week
A better split
Keep talking in your chat. Keep the cookbook, the plan and the list in Yumpair, where both of you see the same, current version.