Sickly? Husband’s Contractual Wife

Reading manhwa Sickly? Husband's Contractual Wife / 体弱多病？丈夫的合约妻子 / 병약한? 남편의 계약 아내

Summary:

I’m Selena, a daughter born to a family well-known for their fertile women. I was all but sold off in a marriage to a sickly duke whose life hung in the balance, all for the sake of producing an heir for his family. They provided me a medicine purported to aid in pregnancy, and the astrologist advised me good days for sleeping together, but... there was no child.
“So, are there any signs of pregnancy?”
“Ah, I-I'm sorry.”
“You’re useless. What luck do you think won you the position of the duke's wife?”
I couldn't say a word.
‘No, excuse me. I only have to look at the sky to pluck a star. That's how I attained this position.’ *