From what we can see. If say what is going on in there relationship is very much "my money is my money, your money is your money unless an emergency happens or I feel like splurging on you" with a mixture of "dont ever talk toe about bills or even look at them. I will handle them 100% and you wont ever need to look at them ever. I had this house before you got here afterall".
I think DSP keeps his financial records directly to him alone and only shows kat a bill or two like utilities or the Mortgage if he ever needs to justify anything or explain a lie out to her when she gets suspicious.
I cant imagine that their marriage is a healthy one with Give & Take status