Not to reign on your parade ...
Having spent time in Korean/Japanese KTV and Hostess bars on business, they are generally very very legit ... in that, you can't do anything in the actual place other than eat fruit, get loudly drunk, sing badly and grope gently about with the hostesses ...
... however if you are that kind of bloke, then its also possible to negotiate with the same hostess girl/girls for a take out ...
In Korea & Japan almost every town/city has its KTV's, Hostess bars and short time "love hotels" ... that's the nature of the way they do things and business ... its not quite the same in HK, but not far off it.
However ... having said the above ... both the korean and japanese businessmen do have a major drinking culture, it is expected if your working for foe a Japanese or Korean company ... as a westerner/foreigner to participate in these outings, oh and absolutely nobody leaves until the boss is ready to go home. Its all about face, business, promotion and cultural expectations... and dont forget the drinking (team building), you collegues get to see you and listen when you are "CUT"
My questions to you are ... do you really know your man, do you understand what he does with his company and what he is required to do to support you? Lucky for you it is only twice a month ... I have known and seen it much much worse
So its really a matter of trust ... just how insecure are you.
Welcome to Asia.
(I presently live in HK)