I recommend this book: https://www.amazon.com/Polyamory-Clinical-Toolkit-Therapists-Clients/dp/1538129884
https://www.amazon.com/Polyamory-Clinical-Toolkit-Therapists-Clients/dp/1538129884
Maybe she could read this book.
My colleague gave me this book: Polyamory : A Clinical Toolkit for Therapists (and Their Clients) https://www.amazon.com/Polyamory-Clinical-Toolkit-Therapists-Clients/dp/1538129884 + it was very helpful