It's the most fought and argued about issue in any marriage. In some marriages, it's a spouse who is in charge of all the finances, the loans, the bills, deposits. Usually the fights come from the fact the one whose not in charge of the checkbook writes checks without the other's knowledge.
Checks bounce, and tempers flare.
In others, one makes the deposits and transfers the money, while the other is in charge of the bills and checkbook. That way both are knowledgeable about the money situation. It all comes down to communication. Tell your mate what checks you've written. That's undoubtably the key here.