I have to say 'The Night Circus' by Erin Morgenstern is an absolute masterpiece. The romance between Celia and Marco is woven into the very fabric of the magical circus, making every interaction feel like a spellbinding dance. The way their love grows amidst the competition and the enchanting backdrop is pure poetry. Another favorite is 'Uprooted' by Naomi Novik, where the slow-burn romance between Agnieszka and the Dragon is as fierce and unpredictable as the magic they wield. The tension and eventual tenderness between them is everything you'd want in a fantasy romance.
For those who love a darker, more intense vibe, 'The Cruel Prince' by Holly Black delivers with its enemies-to-lovers trope. Jude and Cardan's relationship is a rollercoaster of power plays and forbidden attraction, set in a faerie world that's as treacherous as it is beautiful. And if you're into epic, world-spanning love stories, 'The Bone Season' by Samantha Shannon offers a unique blend of dystopian and fantasy elements, with a romance that's both heartbreaking and hopeful.
Don't sleep on web serials and indie publishing! Some of the most nuanced fantasy with understated romantic subplots I've found are on sites like RoyalRoad or from small presses. Because these writers aren't always following market trends that demand a strong romantic lead, they often let relationships develop organically from the plot. The focus stays on the world and the magic system, with characters sometimes realizing their feelings chapters after the reader did.
The caveat is you have to wade through a lot to find the gems, but review communities for these platforms are usually pretty honest about the plot balance. Look for stories tagged 'Progression Fantasy' or 'Low Fantasy'—they often have the kind of plot-driven narratives where romance is a seasoning, not the main course.