Personally, I'd prefer to see all the genres to which NTR could apply redefined using Western terms, and then restrict the application of any of the Japanese terms to games with a demonstrated understanding of the subtleties of the concepts. Use cuckold/cheating/hotwife/swinging/etc. rather than netorare/netorase/netori.
The main character of this story is a boy of 12. His father either left or passed away long ago. His single mother has been diligent, working hard to keep food on the table, help him with his studies, keep up the house, etc. She's the model mother, maybe even greater than anyone could expect. But one day, she gets hurt. Maybe it's a car accident, maybe it's something work related, but regardless, she's hurt bad enough that the doctors prescribe her some sort of opiate pain killer. She eventually gets back to work, and things seem to be normal, but, something has changed.
She's grown addicted to pain killers, and at first, it's not too bad, stretching the budget a little thin allows her to keep up her new habit, while still being supermom, however, her tolerance increases, and with it, her need for more. The food budget gets really thin, instead of nice, healthy meals, boxed foods that are cheap and barely nutritional fill the cupboards. What's more, time, she doesn't have any to spare if she wants to get high, and so she gives less attention to her son's studies.
Eventually things get even worse, she starts neglecting work, gets a rough boyfriend who keeps her high and uses her as he pleases. The son is constantly missing meals now, his health is declining, his sleep is interrupted by his mother's naughty screams. Eventually, the boyfriend is bored of her though, things get even worse, she is unemployed, forced to turn tricks to pay for her habit. She lashes out at the kid, they lose their family home and end up in a really small flat. You get the picture by now.
This story is for all intents and purposes one of Netorare. The boy has a relationship consisting of a bond of trust with his mother, that of the maternal variety. The introduction of opiates into her life steals his mother from him, perverting the bond between them, breaking it, making it so that he can no longer recognize his mother in this woman. That is netorare. There's no need for cheating. No need for cuckoldry. No need for any of the specific sexual tags you proposed. And that's the major issue with how people view NTR in general. They think NTR is about a single act, about a single emotion. But no, NTR is a theme, it's an overarching journey. You can't replace NTR with english tags because we don't have a word for this.