As title.
Using Flex is great but our money is mainly managed via joint account. We both have separate Flex accounts that we use occasionally for family things.
Right now if I’ve bought something on Flex my wife has to send me half to my personal account each month manually.
Being able to pay my Flex payments from the joint account would make the whole thing so much easier 
What you are describing is a good old fashioned credit card with an additional card holder.
Not really. My understanding is the OP wants to settle his Flex card from his joint account but currently Monzo allows only paying for Flex from personal account.
I, same as OP, would want to settle my Flex from joint account or joint pot
You can settle a credit card from a joint account.
Of course, but this is a Monzo forum and my post is about a Monzo product and possible feature enhancement.
It’s a suggestion.
“Just get a credit card" isn’t exactly helpful. I want to use Monzo Flex, the pay in 3 options and the ease of management that Monzo provides.
As was my suggestion.
100% agree - we use my flex and settle at payday. I should be able to set it to pay from joint - I see no reason why you cannot settle from joint.