Human relationships are not easy at the best of times, especially when partners are of differing ethnic origin,because you have family and extended family on each side,to consider the implications of any relationship, or for that matter a simple friendship,Japan is a very nationalistic and ordered society where in most cases the group matters,especially family and extended family,this also extends to the workplace where things are usually done as a group,perhaps this is a kind of Beehive mentality that Westerners and others find very hard to mentally get their head around,when in the Western society many functions are based on the individual working and functioning alone,Japanese are usually very polite and orderly,there are some exceptions to this,but usually a drastic loss of face returns these people to (normal) traditional Japanese values.