What makes a relationship romantic?

Respect: Mutual respect is key to a romantic relationship. Each partner should value and appreciate the other’s opinions, boundaries, and individuality.
My favorite historical novels are those where the main male character goes against societal norms in that he actually respects the main female character. If he admires and supports her, all the better. Yes, this is atypical for the time periods that I read and write in, but this is a trait that makes you absolutely fall in love with the hero.