Not sure about Japan but what I noticed on sites like the f95zone forums is that the people who are specifically opposed to NTR seem to have an unhealthy obsession with it when compared with the people who just don’t like most other kinks, even compared to kinks most people find distasteful or morally questionable.

Have you noticed any kind of escalation in the kind of sex you need? I am thinking of something like trying more and more extreme kinks as more vanilla stuff gets boring or similar changes that make you wonder where this will take you in the long term.

Probably being towards the compersion end of the compersion vs. jealousy spectrum. It gets tiring very quickly if a partner gets jealous every time I interact with someone who might conceivably be attractive to me.

For that matter a certain minimum amount of self-esteem is good to avoid having to examine every word and action twice with them in general.

Cuddle with one girl on each side afterwards?