Some people behave the way they do because nobody has ever asked them to do something differently. Since you care for her so much, it would be good for both of you to offer her an alternative way of behaving, one that givers her the chance to show you more compassion and caring than she has so far.
But if you keep a calm head and tell her how you feel and what you want and she still dismisses it and acts as if you have to do poly her way or no way, I would hit the road too. You certainly deserve to have any partner, whether poly or not, willing to take your feelings into account.
Happiness will never come to those who fail to appreciate what they already have.