The Mercurial Duke's Stand-in-Bride

Married only to bear an heir.
"No matter how much I love and hold you, it's never enough."

"You're so wet already. Did you want a man that badly?" Cecelia, the adopted daughter of a viscount was married off to Lucas, known as the Mercurial Duke, as compensation for her brother running off with Lucas's fiancée.
"I don't need love. All I need is an heir." Lucas said that to Cecelia, but their love-making is gentle and sweet, so Cecelia gives up her body to Lucas's ferocious desires. Cecelia genuinely loves Lucas, so she tells him she wants to bear his baby, and Lucas falls in love with her honesty.
But then they receive information that a noble who fears that Lucas will reveal their wrongdoing has hired a talented assassin to kill him!