Yeah this is my only issue with the way they framed this particular plotline. Damien even said it himself, “you much live to give BIRTH to our child.”
The whole point was the illness was very likely to kill her BEFORE she had the chance to have the child, and she was still so early in pregnancy there was no telling she’d be able to hold out months to go into labor. She wouldn’t have had the kid regardless.
It would have made way more sense if the issue was she’d die in childbirth, which would have prompted Damien to pick between the two and force her hand. But in this scenario, he technically would have lost them both because of her sickness. just my thoughts. I can understand her still wanting to divorce him, especially because of the other things she found out about him, but I can really blame him much for this instance.
The thing is she would have died before the child even lived. It would have been different if she could survive til birth but she wasn’t so it was a hard choice..