Beauty and the beast! The lady or the tiger! Kirsty Logan's The Rental Heart and Adam Roberts' Bête - two thought-provoking books about well... you'll see.
Kirsty Logan's The Rental Heart (2014) is a slim volume that packs a whale of a punch. Although the collection's 20 stories are all (to generalise wildly) on the theme of 'love', it captures a huge variety of emotional nuance: from heartbreak to resentment to loneliness to pure, unwatered desire.
Logan's style is deceptively ephemeral - the stories are often phrased like fairytales or delivered like children's stories, but they're neither: they're meaty, visceral and, on most occasions, utterly ruthless. Virtually all are genre-inflected: Logan captures twenty worlds where relationships are unbounded by the 'rules' - physical or otherwise.
One of my personal favourites include "Underskirts", the story of a beautiful countess who hand-picks peasant girls to become her lovers. Told from a dozen different points of view, the tale is alternately horrifying and uplifting - is the countess the saviour or the villainess of the piece? The story spirals in closer and closer, with every perspective adding something new to the mix.
Another, "The Broken West", is less ambiguously forlorn. Two brothers search for their missing father - in the most heart-breaking of ways. Their own lives degenerate into a haze of self-destructive sex and alcohol, as their (impossible) quest takes its toll. As with "Underskirts", "The Broken West" describes the lingering impact of a single person's actions - a domino effect of broken lives.