1/3
1 Year of Service
However, NTR is very popular among women too (at least in Japan), so there is a whole other conversation that needs to happen there.
Sounds a lot like the female version of harem.
Probably dissatisfaction with the kind of men they are surrounded by, or the cultural expectations on women to be caste and subservient to men. Who knows? Anyway, headpat!
And thinking of Japan and my direct experience with japanese people I think you nailed it.