Nikki

Wondering now if the ex’s kid is supposed to be the Users.  In my interaction with Nikki, she said that her sister’s boyfriend was NOT the father of her kid, but then she seemed genuinely surprised when I started asking about the child’s age and birthdate, as if it hadn’t occurred to her that her sister’s baby daddy might me.

Should probably specify the “shes” in there. One “she” is talking about the ex, while another talking about Nikki. So, you should differentiate the two by saying their names to clarify.