Hi @kaizengrit I agree that splits wouldn’t quite work here since the use case for splitting a transaction is for when a single purchase can be split into multiple categories.
Have you utilized a note column in your Transactions sheet or tags?
I think your best bet would be to use Categories, Tags, and/or a Note on the transaction then review on a regular basis (maybe monthly) with the other parent. That way you can notate what needs to be reimbursed x amount, you can review the data in your sheet by those specific accounts (the shared debit card and the rewards credit card), or better yet you can have a spreadsheet dedicated entirely to purchases only from these cards. Then the Categories, Tags, or Notes can help you organize everything.
An example:
Category: Child’s name
Tag: Type of thing child needed (clothes, food, sport, school cost, etc.)
Note: spouse paid me on March 30.
Then when you need to see all of this in one place you’ll just filter your sheet to only show transactions with Category: Child’s name.