The story goes that the protagonist, Arai, has been abandoned by his ex-wife (and unknown number of kids) after she cheated on him and got married to her affair partner, who is apparently some rich guy. In the resulting tormented state, he discovers that you, the heroine, are cheating on your own spouse... And decides to take his form of revenge by becoming your next affair partner(???)
This is the only work I've listened to in full for this series, but from the others' samples, it seems that Arai's been listening in on you and your previous flings... Truly the neighbor advantage.
The VA's acting was great and really brought out the bittersweet sense of encroaching despair, even while the characters deepen their relationship from neighbors to partners in NTR... The shifts in the protagonist's tone from affable mild-mannered neighbor -> suspicious yandere accusing you of cheating on your husband -> shocked guilt when he realizes your husband knows -> desperation when he begs you to leave your husband for him >>>
Last but not least;; the swing sound effect for the tokuten sounded like something straight out of a horror movie! But I really liked how the ending retains that bittersweet melodrama vibe and a temporary happy ending (at least until your husband comes home... For better or for worse </3)