Cane was infertile and Iris knew that fact since the beginning. He wouldn't have a baby on his own, though it had never been mentioned again and she had never thought about it too deeply, the King's demand was always at the back of her mind.
In rare times, Iris wondered what kind of plot Cane would create to get away from it. What if the time was up and he was still without a child? Would he blame her for that? Iris didn't think Cane would do that to her.
And now, Sofia came and everything was crashing down around her when the realization of what Cane would do sank in, the possibility of him even thinking about it crushed her broken heart.