I am so sick of the Manichean construct of contemporary novels and comics. It is as if the concept of nuance, the concept of empathy, and the concept that circumstances shape people as much as people shape circumstances have died with the advent of the 21st Century!
Balzac said: "Literature is the intimate history of a nation."
But we are not there anymore, we are not trying to elevate the human spirit with art, we are just trying to get a cheap thrill. We need the villain to be slain for us to sleep better at night. And Lord forbid there is a fleshing out of the villain, that will lead just to much more backlash. I have seen the efforts of great artists (I am thinking of TUTU'S "The Queen" Season 1) to explain how circumstances shape people in one of the most incredible characters in history of Chinese webcomics (who did do evil and who knew very well why she did it - let me tell you a secret, it transcended petty hatred and implied greater ideals, such as saving a whole ethnicity from genocide) was drowned in the shocked outcry of the fans. Gee whizz, the evil consort is in fact the leader of a whole people and has sold herself off, body and soul, to save them!!!
Sorry, I had to get this off my chest.
You asked whether anyone ever did an anti-villain and hero romance. Indeed, one of the greatest modern authors, the father of psychological literature, did NOTHING BUT! Dostoevsky's "Crime and Punishment" is the love story between an innocent, pure girl who sells herself off into prostitution to support the children of her father's wife (who are not even one bit related to her) and a man who suffers from a horrid duality, on one side he committed a sordid murder and did not even blink an eye on the other he is tortured by his impulses of empathy and compassion. It is a tale of redemption through which love blossoms.
It is not done often. It is not satisfying enough for us. We like for the villain to suffer, it has to do with innate cruelty. As long as one commits a misstep, as soon as someone's ideals do not align with the social accepted scale of good and evil (though we never question whether that scale is even in touch with reality - as long as everyone agrees on it, it is perfect and must be accepted, if need, under coercion), we are ready to tear him apart.
If you plan on writing a tale of two people whose ideas and ideals clash, who are on two opposing sides, whose scale of measuring good and evil does not give the same result and who need to battle through these difficulties in coming together, while at the same time feeling incomprehension at how love, attraction and desire could have sprouted between the two of them, then count me IN!!!
I have been waiting for it ever since 1866.
I am sorry. I am hangry.