A Japanese business partner once told me how personal finances are managed in Japan:
Regular pay checks are put into an account, which is completely controlled by the wife. The man only gets pocket money. If he gets to a certain level of wealth, he opens up another account, where additional money is transfered to by the company, which he basically needs to afford his concubines. Any truth to that?
My understanding is that women don't "control" the finances, rather, paying the bills and running the household is their responsibility in the same way that a traditional Western man would expect his wife to have dinner on the table when he gets home. She might handle the money for household expenses but he would still be the HNIC. Your business partner sounds like quite the nyobo koko no teishu.

Concubines? Haha. I'm sure it still happens, like the Soprano's guma, but I bet most guys would simply take a prostitute. Old drunken businessmen with a group of beautiful young women is a very common sight and doesn't seem to be frowned upon anywhere near as much as in the West.
Japan is definitely a man's country. A lot of Westen women would find the place overtly sexist.
Hey DK, how was the trip? I've been meaning to PM you since I took up judo recently. Have you studied any martial art in Japan? Been to the Kodokan by chance?