Money rules -(disclaimer - I am not a financial advisor and this is not a financial advise or guide )
Have at least one secret bank account.
Have statement suppressed / online only
Don't tell your partner your real after tax income - maybe deduct $200-$1000.
Get your salary paid on this secret account. Leave that $200-$1000 in there transfer the rest back to your regular account. Payment reference salary.
There you go... Have surplus in your account do what ever spend it...