NTR definition is one of the most controversial topics in porn. It has been debated to death and still there is no consensus. It is up to the player to determine if it is NTR for them. Who said that the player doesn't have a romantic relationship with Ashley? Ashley certainly thinks so. It's up to the player to decide that. Who said that the player was 100% OK with Maria taking over and eating out the creampie the player just gave Ashley? It's up to the player to decide that.
It's all a matter of perspective. Some people have a broad definition of NTR and some have a narrow definition of NTR. No one person has ownership of the NTR definition. "Please, don't misuse terms."
I have over ten years of experience in Japanese hentai comics and a good chunk of that experience involves netorare. The definition is not at all unclear. The word refers to a romantic interest being
taken by someone else. There is no philosophical minutia to be accounted for and there is no broad or strict sense. For something to be taken from someone, that something needs to belong to someone in the first place.
If there is no romantic bond in no form nor fashion it is not netorare because its basic requirement isn't met.
The scene you referenced has three characters in it, none of whom have any bilateral bond at that time. The only romantic interest is nurtured unilaterally by Ashley (and no, headcanon doesn't count), so there is no bond to be broken by taking away someone from someone else.
Even admitting a relationship exists between the MC and Ashley, there would still be no NTR because no one is snatching away anyone from anybody. The sexual act is among the two people involved romantically and the third just watches (voyeurism, not NTR). Then we have the third licking one of the members of the couple; this is still not NTR because this act doesn't constitute per se a breaking of the couple's bond in favour of the third person and there is no complaint by the MC - thus it could be at most netorase, that is the act of letting someone else enjoy your love interest.
In conclusion, netorare is a genre in which a bond is broken to the detriment of the character the audience is supposed to identify as, not one in which a bond is shared. It is supposed to evoke the negative feelings of being cheated on. The scene you referred to doesn't do that, it's from start to finish a three-way act with consent from all parties involved and no hurt feelings.
Look up the differences between netorare, netorase and netori to get a clearer picture. You did misuse the term. No hentai comic ever would call itself netorare in its title because of such a scene.
The only thing controversial about netorare is that some people hate it with a passion. Nothing more.
