It is actually 3-4 separate tags on Scribble Hub.
Assuming: A is married to B, C intervenes, B decides they like C more than A.
Netorare would be from A or B's perspective
Netori would be from C's perspective
Netorase would be from A or B's perspective, and their partner is pushing them to cheat on them
Adultery would be used if B never actually cared for A in the first place.
All of the first 3 are included under NTR...
...And all of them can go die in a thermonuclear fireball (Adultery too).
I should also note that nearly all of the NTR stories added recently have been proven to be Chinese translations. These are, strictly speaking, not allowed on SH and have been, for the most part, de-listed.
Unfortunately, Tony tends to be soft on enforcement, so they are only de-listed, not deleted.