Married with separate accounts here! I’m a spender, the spouse is a saver. (no kids)

We addressed transparency by actually turning all accounts into joint accounts. So, technically we could access eachother’s banking and credit cards at anytime if we wished (which is recommended for emergencies). We also have quarterly meetings with a financial planner, so all of the accounts are reviewed together pretty regularly, just not day to day.

Trips/large purchases are handled the same way as daily finances. Costs are divided in line with the percentage of total household income that we each bring in. But it helps that neither of us nit-pick. It’s not an exact science. We take turns buying dinner. We always say thank you. Example for a trip: the higher income earner buys the air and the lower income earner buys the rental car.

The only rule that we have put in place is that if one of us is going to make a purchase larger than $200, we pass it by eachother as a courtesy.