Ah, okay, that makes sense. Anyway, the "NTR" tag on F95zone is referencing "Netorare", which means "getting cucked" in japanese, where the protagonist/MC gets cucked (as opposed to swinging, where the cuckoldry happens willingly, NTR happens to the MC without the knowledge or acknowledgement by the MC).
A different term to cuckoldry is the term "Netori", which is where the MC/protagonist cucks other males, i.e., fucking someone's wife/girlfriend. The NTR tag on F95zone seems only to apply to "Netorare", not "Netori". "Netori" is no different from rape, and is considered in most cases under that fetish, or male domination.
Anyway, when people use NTR or talk about cuckoldry, they popularly refer to "Netorare" rather than "Swinging" or "Netori".
That aside, thanks for the clarification.