The Art of the Slow Burn: Building Romantic Tension Without Losing Momentum

Craft essay.

In a good romantic thriller, love is not a fast burn. It’s a delayed ignition. The tension comes not from the spark catching fire, but from everything that resists it. A look held too long. A brush of fingers that’s quickly withdrawn. These are the moments that keep readers glued to the page.

Writers are often told to raise the stakes, move fast, and keep the pages turning. That’s how I learned to write thrillers. But in romantic thrillers, sometimes the power move is to slow down and let the fuse burn long.

In The Bjorn Identity, Justine Dupleix and Ash Durham don’t fall into each other’s arms. They fall into an assignment, into a ‘cover’ marriage and all the way into mutual irritation. From the beginning, their relationship is defined by opposition: she’s meticulous and guarded, he’s breezy and instinctive. She plans. He improvises. She can't stand how he never takes things seriously. He thinks she’s wound too tight. Their differences become the drumbeat of their every interaction—and it’s in that rhythmic clash that chemistry begins to take root.

A slow burn builds beneath the surface, often somewhere beyond the characters' own awareness. They argue, compete, sidestep, and sometimes try very hard not to notice each other. But the reader sees it coming long before they do. And that anticipation is the engine of the story. It creates emotional investment and turns the smallest gestures into loaded moments.

But how do you keep a reader turning those pages when your protagonists spend the first hundred or so kind of pissed at each other?

Raise the emotional stakes a little higher than the plot stakes. In Bjorn, the physical danger is real, but the emotional hazard is more acute. For Justine, letting someone in means discarding the armour that’s kept her safe for years. She’s been trained to trust no one, compartmentalise her feelings, and win at all costs. Vulnerability, to her, is failure. For Ash, admitting he cares means becoming vulnerable in a way that doesn’t fit with the charming, unbothered persona he’s perfected. Beneath the jokes lies a deep-rooted fear of not being good enough.

Let the action drive the intimacy. Suspense can be your best friend here. Forced proximity. A shared secret. A narrowly avoided explosion. These are classic genre beats for a reason. Well, okay, maybe not the explosion, but I’m coming from a different genre, which is full of SPLOSIONS.

These beats let the reader meet our characters when they’re caught off guard or being tested under pressure. When the mission goes sideways and they have to rely on each other, they start to see what the other is truly made of. If it’s a good enough principle to apply in real life, it's gonna work for fiction, too. One high-stakes situation can do more for romantic development than a dozen candlelit dinners.

Let your characters press each other’s buttons, not just to annoy, but to reveal. The more they struggle to maintain control, the more the reader senses how close they are to losing it. Tension thrives in contrast: the cold shoulder after misperceived rejection, the apology that didn't come, the moment when one of them almost says the thing they shouldn’t.

(This reminds me of a favourite New Yorker cartoon in which a woman in a very obviously heated argument with a man says something like, “I think we’d better stop before we both say something we really mean.)

And when someone finally cracks, it should feel both inevitable and shocking, like a dodgy emotional dam giving way. Make it count. Collapse should come with consequences. In The Bjorn Identity, the first kiss isn’t a reward. It’s a shift in the power realities of Ash and Justine’s relationship. It obviously changes how they see each other, but more importantly, it complicates what they’re willing to risk.

Don’t rush it. Let the spark smoulder. Let your characters deny it, deflect it, talk circles around it. And then, when they just can’t anymore—when the story, and the reader, and the characters themselves demand it—dump a big ol’ can of gas on things, and stand back.