I would try to find another therapist. I know it was probably hard to find this poly-friendly therapist--but something about how you describe your first session with her sounds really "off" to me. Her approach and her attitude towards you sound wrong.
--Speaking as someone who spent several critical months with the wrong therapist, but felt too guilty to stop seeing her because I thought I was right to keep pushing myself and keep facing hard "truths."
Single, straight, female, solo, non-monogamous.