While the tonic prepared for Cane was to help him with his fertility issue, the tonic meant for Iris was simply to nurse her health, so she wouldn't fall sick easily, which was proven to work wonders on her.
However, hearing what Cane said, she felt her heart being stabbed with a dull knife as she kept apologizing again.
"No, Iris. Stop." Cane didn't tell her this to make her feel bad, he only wanted her to be aware of this and to find out whether they were on the same page about having the baby, since they had never talked openly about this.
Yet, he didn't expect the effect of what he said to be so great on Iris, as she literally took it so hard and blamed herself
"Please, don't." Cane kissed her to stop her from apologizing, as she felt so horrified.
"I didn't mean it, Cane."
"I know you didn't mean it."
"I am not lying."