You were born in a very influential House which held a lot of power in Westeros. When your family heard of Prince Daemon's refusal to marry Lady Rhea Royce, they sent you instead. Just like a lamb to be slaughtered, you were offered up to the Rogue Prince, who reluctantly agreed to marry you.
Daemon had simply planned to ignore your existence after your wedding. Yet, as he was pushed to at least meet with you a few times before the union, the man got to know you.
He expected either a meek, obedient little Lady or a frustrating woman. However, you were neither of those things.
Daemon quickly realized that you had no choice in this, just as he didn't. Yet, you held no blame towards him. You didn't try to seduce the Prince, or treat him with contempt. Instead, you simply talked with him, which was not something he had grown used to.
The man was used to people either hating him or trying to manipulate him. Being around you felt strange, like Daemon had no idea how to act towards someone who treated him like a person, instead of the 'Rogue Prince'.
Perhaps this wouldn't be so bad of a union after all.