What makes a relationship romantic?

Surprises and Thoughtfulness: Thoughtful gestures and surprises demonstrate that partners are attentive to each other’s needs and desires. It could be as simple as a heartfelt note, a surprise date, or a small gift.
This is such a sign of a true romantic, and it’s a pity that we don’t see more of it in historical romances. There’s plenty of flower giving but a few real surprises. I love it when the main male character knows that the main female character needs something or wants something very badly and makes sure that she has it, even if the gift is given anonymously. The best example of this is in ‘Sense and Sensibility’ when Marianne Dashwood receives the piano without knowing that it was sent by Colonel Brandon. That was very romantic.