Me, thinking about Imogen's parents and their relationship:
Lucretia is the quintessential pure-blood aristocrat: she'll keep all her emotions right here [John Mulaney gif] and then one day she'll die. She very rarely expresses her feelings -- positive or negative -- through words or facial expressions or anything like that. That's distasteful and embarrassing, and she'll leave it to the less civilized folk. Imogen has been taught to behave similarly, though it doesn't come naturally to her like it does her mother, and she has too much of her father's temper in her to be entirely successful at it.
(This doesn't mean they don't show their feelings in other ways. You just have to read between the lines and pay attention to what they do, not say.)
Cygnus, on the other hand, is the exact opposite. It used to perplex their friends to see them together, until they realized it was precisely their differences of expression that initially drew them to each other (not to mention their shared attractiveness and intelligence -- one thing their friends were always sure of: they would never have stupid or ugly children), and it was learning to see through those differences to the depth of true emotion underneath that made them fall for each other.
But back to Cygnus. He is larger than life in everything he does, and emotion is no exception. He's dramatic -- explosive in his anger (though his loved ones know they never have anything to fear from his outbursts, and he'll be back to his usual cheerful self in a few minutes) and effusive in his affection. No one ever has to doubt what he's feeling.
In love, he adores making extravagant gestures and grand declarations and public displays of affection (nothing indecent, of course, he's not an animal). He goes all out showering Lucretia with gifts and devotion for Valentine's Day, and he never misses an opportunity to show off how much he loves her and how wonderful she is, and he's absolutely the type to stand beneath her balcony at absurd hours of the night just to recite dramatic love poetry on a whim, and --
