YESMISSA:
But why will they live together? And will they live together long enough? how will it be for SHANGGE? you said she'll forget what she did as Houchi, but what will she do when she sees him living with the other girl? and the child will be conceived when? and when he is conceived will he still live with the wicked one?
Ok, let me try to explain, its a bit complicated.
First, the child is conceived before Bai Jue awakens, but born after. Bai Jue rejects the child (again, part of his plan, he is hurting inside). Shang Gu doesnt know Aqi is hers, she thinks is his child with a mortal woman, she thinks he is over her, but still says to him he should take responsability for Aqi even if he doesnt love the mortal woman. In this arc Bai Jue is in the Demon World and Shang Gu is in the palace with TianQi so she does not see him often. Bai Jue stays with Jing Zhao not because he likes her, but he is using her to keep Shang Gu away. When she sees him with the other girl she is sad, obviously but she doesn't push in.