In my opinion, there are two possible reasons, why Olivia would love to have a baby.
On the one hand, there’s the fact that she is alone. She has Harry and the Nawab, but if she had a baby, she would have something to care for, a new occupation. Something like a task, she has to fulfill
On the other hand, this baby would be another connection between Olivia and Douglas. If Olivia is together with his baby, it reminds her about Douglas. Perhaps it would look like him and Olivia would love to have a part of his husband with her the whole day. In addition to that, the relationship between her and Douglas would change, too. They would have something else to talk about. Above all, Olivia and Douglas have not much in common, concerning their daily life. This baby could strengthen their relationship.
