Well said, in regards to the succubus I would add that I feel like part of the struggle with monogamy for them stems from the trope of potentially killing their partner if they solely feed of them cause it either permanently or at least temporarily drains their life force & often enough that's either something the succubus can't prevent from happening or essential to keep themselves alive.Sure, the monogamy wouldn't fit with the most common depictions of succubi.
But authors aren't forced to adhere to that - look at how many related but different portrayals of various fantasy creatures there are - whether it's elves (immortal or long-lived, first-born or refugees from another world, generally good or just arrogant (or both), inherently magical or just as magical as humans) and dwarves (sure, short - but can they use magic or are they inherently anti-magic? Do they have guns? Are they primarily driven by greed, grudges, vows or more similar to humans? Do dwarven women always have beards?) or vampires and werewolves (compare world of darkness with various other systems/settings).
The common conception of the creatures provides a shared basic idea from which an author can then borrow and adapt, changing aspects so that they fit their vision - relying on the shared understanding to ensure the audience has a general picture and expectation, and then introduce their own variations and twists on top of that. (If I tell you you play a xzaragar, that won't do anything for you. If I tell you you play an orc, you've got basic idea - that idea might be partially wrong depending if we're talking Middleearth or Shadowrun, but subverting those expectations is also fun).
Also, I recall a succubus in a recent CRPG that can become monogamous, if that counts.
Anyway, in the hope of getting back a bit from the derailment of both the whining about future optional tags and the reactions to that... on reflection, the switching of PoVs works really well - the first person with visible body helps to convey a physicality and "you being the character", while the occasional third-person views give a good idea of who/what your protagonist is and scene-setting - the last scene of the update for example wouldn't work nearly as well in first person in my opinion (and at least for the female protagonist they also do a good job communicating pleasure).
Since so far it doesn't seem as if that is a thing at all, at least not in a way that would more or less literally force Valerie to resort to go down on multiple different people to stay alive, the potential of a monogamous relationship seems quite convincing, especially since her character comes across as the type to enjoy, if not outright prefer, it that way, at the very least on the protection path.
