Do All Mothers in Childcare Novels Have to Die [Novel]

"I command the King of Niita to bring forth the kingdom's princess. I will return to the Empire with her."
In that moment, I recovered the memories of my past life — just as I became a hostage of the Empire — and realized this world was a childcare novel set in the imperial palace.
And I was the mother who gives birth to the heroine and dies right after, as is tradition in this kind of story.
I didn't want to die, so I tried to run. But the moment I stepped out of the stables, I was caught.
"My hostage was trying to escape, wasn't she?"
It was the Emperor, standing before me.
There was nothing I could do; I was dragged off and made Empress.
So I decided to become a neglected, forgotten Empress who slips away without anyone noticing.
"We must sleep in the same room, you and I."
…Yet why is the Emperor in my palace? Doesn't he have anything better to do?
The Empress Dowager weeps whenever she sees me, saying I remind her of her youth, while the Emperor asks me to keep her away. Mother and son seemed a little estranged, so I tried to mend things between them…
"If His Majesty ever mistreats you, tell me in secret, and I'll help you somehow."
Once the Empress Dowager won back her son's love, things turned out like this:
"I've never been with anyone before, but I can't stop looking at you."
Why is this handsome Emperor looking at me with such sparkling eyes?
I really want to run away.
If I bear this man's child, everyone will be happy — except me.
So why can't I leave this man who whispers that he's lonely?