What makes sex so natural a subject for fiction isn’t simply prurience, but rather the drama built into the evergreen question of how private desire finds expression, not least when the law’s looking. Two new novels, both set in Asia and centred on the coming of age of gay men, play out against the legacy of section 377, the Victorian penal code criminalising homosexuality in British colonies – repealed in 2018 in India, where Santanu Bhattacharya’s Deviants unfolds, and still applicable in Malaysia, the setting of Tash Aw’s The South, the first of a planned quartet from the two-time Booker longlistee.

Deviants, Bhattacharya’s second novel, hops with buttonholing vim around three gay men across three generations over the past half-century to draw surprising contrasts and continuities of experience amid legal and cultural change. The two earliest threads, which open in the 70s and 90s, tell of loneliness, shame, persecution. One protagonist, an artist, lives with the painful memory of a thrilling secret relationship that was snuffed out almost as soon as it began, with his lover, known only as X, curtly announcing his marriage. Another, a university student, falls in love with his university classmate only to be ostracised, with much worse to come.

But the segment that lies closest to the book’s heart unfolds as a series of voice notes in the here and now. Vivaan from Bengaluru – tech-savvy, comfortably out, not yet 17 – tells us how his parents fight his corner when a teacher voices concern about bringing his latest dating-app hook-up, Zed, to the school dance. We’re as uneasy as Vivaan when his teacher, doing a U-turn, smugly congratulates herself for her enlightened approach; ditto when the night itself leaves him feeling as if he’s cos-playing straight coupledom. Yet we’re even more sceptical when Zed responds by introducing Vivaan to the joys of app-enabled polyamory, as they Uber themselves from one multiway rendezvous to the next. “Who would’ve thought there was this underbelly in this boring Silicon Plateau?” thinks Vivaan. “By day, everyone was an IT developer, project manager, venture capitalist and whatnot. And by night, they were… open to being anything.”

It’s no surprise when Vivaan starts asking questions of where he and Zed stand. Twining their story with those of past lives is a way for Bhattacharya to give fairly provocative side-eye to the notion of progress, registering potential losses as well as obvious gains. A plot turn into the farther frontiers of AI leaves Deviants poised between a sober portrait of stymied lives and a bold satire on big tech and the marketisation of sex, leaving us uncomfortably uncertain (victory, for a novelist) about the precise nature of Vivaan’s hard-won freedoms.

Aw’s equally absorbing new novel, The South, unfolds in a gentler key. Set in rural Malaysia, it has a more classic coming-of-age setup, taking place over a single summer during the teenage narrator’s school holidays. We’re somewhere in the mid-2010s (there are corruption allegations against the disgraced prime minister Najib Razak), when Jay pitches up from his unnamed home city with his Chinese-Malaysian family to figure out how best to deal with the long-neglected farm they’ve just inherited after his grandfather’s death. Gruffly dispatched by his dad to make himself useful on the land, he spends long days in the company of Chuan, a shrewd young farm worker in the family’s employ: Jay’s first cigarette, first beer and first kiss all ensue in short order.

His cross-class relationship, built on swims and scooter rides and fuelled by lingering glances and, eventually, secret trysts, unfolds with unsensational reserve against the backdrop of wider family upheaval caused by revelations about Jay’s father, a university lecturer facing pre-retirement redundancy in a case of long-brewing sectarian discrimination. The double life he’s shown to have led holds up a mirror to Jay’s own, and supplies one of several contexts for the novel’s delicate airing of age-old questions about what it means to be a man.

Hushed in tone, leisurely and episodic in the telling, the book adopts the perspective of a range of characters besides Jay, making quietly clear that his older sisters’ desires also must find form within the confines of expectations. Lina won’t tell their parents about her Malay boyfriend for fear of what they’ll say; a worry confirmed by the casual bigotry of Chuan, whose views repeatedly grind against the righteousness of the novel’s big-city blow-ins, whether he’s standing up for the bulldozing of ancient forests or laughing at Jay’s question of whether they’ll be “able to hold hands in the street one day, somewhere”: “Don’t you have better things to think about in life?”, he responds, crushingly.

The personal is political, but these novels – each smart and engaging, The South interior, Deviants expansive – unsettle the instrumentalism implied by that old saw (“What if same-sex love is not an act of resistance, what if that is just how it is for some people?”, asks one of Bhattacharya’s gay narrators). Yet for all that these books are interested in looking hard in the eye at rehearsed narratives, they leave no room to doubt what all their protagonists know full well: there’s always such a thing as society.

Deviants by Santanu Bhattacharya is published by Fig Tree (£16.99). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply.