You've landed on a genre intersection I can't get enough of. Gothic romance at its best absolutely thrives on that tension between a dangerous, magnetic attraction and the slow, chilling unraveling of a family's rotten core. It's not just a gloomy manor; it's the feeling that the very stones are stained with sin, and the person you're drawn to might be part of that stain.
A classic that defines this for me is Daphne du Maurier's 'Rebecca'. The romance with Maxim de Winter is shadowed from the start by the spectral presence of his first wife. The dark secret isn't just a past murder—it's the entire toxic legacy of Manderley and the de Winters' pride, which almost consumes the nameless narrator. The romance is inextricably tied to uncovering that ugliness.
For a more contemporary, visceral take, Silvia Moreno-Garcia's 'Mexican Gothic' is a masterclass. The protagonist, Noemí, goes to rescue her cousin from a distant family estate, and the 'romance' with the heir, Virgil Doyle, is deeply unnerving. It’s a dance of manipulation and survival where the family secret isn't a single event but a biological, decaying evil woven into the house and their bloodline. The attraction is laced with genuine horror, making the eventual defiance so much sweeter. It’s less about a grand love and more about breaking a dynasty’s curse.