A) Does she do all the slutty things behind her boyfriends back, or is he aware of it in some way?
Let me guess. The boyfriend is incapacitated somehow in the start of the game, then you never see him again, right? So the whole time on her adventure, she gets corrupted, occasionally saying, "oh i feel so guilty, my boyfriend, but it feels too good, this is so wrong". Right? So the boyfriend is completly unaware of her cheating, perhaps until the very end of the game (classic netorare)? Nothing wrong with this formula, I'm just trying to gauge exactly what type of NTR this is.
B) Or does her boyfriend come along with her and bear witness to her debaucherous corruption?
I'd probably put this answer into original post, because anyone interested in NTR will want to know PRECISELY what kind of netorare it is, since NTR has a lot of sub-genres.
Question: Who is actually saying "Those plump lips would be better wrapped around my cock?" Does the female protagonist have a dick, or can we read the minds of her party members
(which is stupid and breaks immersion IMO, unless of course it's explained why she can read minds, maybe due to some mind reading ability. Now, if a party member wants the blonde in purple clothing to wrap her lips around his cock, how can that be understood from the perspective of the female protagonist? Perhaps the female protagonist (girl with red hair) notices that her male party member companion as a bulge in his crotch, and he's focused on the blonde girls lips, implying he wants those lips wrapped around his bulging erect dick, instead of the female protagonist being able to magically read his mind; this would preserve immersion. Important aspects like this are neglected by most porn game devs, a bad habit that started with lazily made JRPG porn games.)