At most in the never-finds-out-ending she may still do it just to keep up appearances, after all part of Kirito never finding out will have to be eventually making him believe Inoda's children are his I would imagine, as per his extreme lack of luck, especially after Sugu's seemingly complete character reversal in the last update meaning the universal rule of Kirito not getting anything 'good' is holding XP
You think most NTR writers care about those details XD? In modern-day, as long as a girl vaguely related or interested in the MC, even if it's completely one-sided or the MC never finds out, gets fucked by another dude, it's immediately tagged/promoted/named as NTR, hell, practically every piece of SAO NTR that uses non-Asuna girls is specifically framed like that because of the series' unique nature in that regard
Most writers/readers just don't care, they still take it as NTR as far as they're concerned.