For what I assume is the majority of married couples, it's at least or more straightforward to share finances and know that there is no debt, or if there is, exactly what it is. We rarely discuss finances, certainly not "constantly", as there is no need because we both have access to it and the information.
We each have individual daily spending credit cards, although are authorised users on each others. DH has Amex, I have Mastercard, so they are used by both where they are accepted or will gain the best rewards. Both with a DD to pay in full each month.
If I spot an unusual transaction on my card , I will check with DH if it was his purchase, in case it is fraudulent, but don't question the specifics of what he bought. I might gently tease him if he bought a sneaky treat from a bakery on my card for example, as I get notifications of transactions, but he has the option of a different card or cash, so could make the purchase without my knowledge very easily. I think he does it on my card as he likes being "caught" though 😁.
We discuss large purchases like appliances, cars etc, but otherwise trust each to spend within our means. Large purchases that might use finance or the need to borrow on a 0% card is managed by me, as DH trusts me to do this, but I would update DH every so often (every 6-9 months perhaps), so he has a general idea.
One reads on here quite frequently that OP's partner has secret debt, which remains hidden and gets out of control, and that can cause the end of the relationship. I'm glad my DH and I have full transparency, and I appreciate it all the more after being in a previous relationship that did not.