Glad to see things are looking up. It is probably best to keep the poly talk on hold until she works through other issues she apparently has. To begin the conversations now may only scare her or anger her back into her jealous, insecure ways. You know her best and you can judge when and if she will be ready better than any of us.
But in the end you may have to make a choice, if she is completely mono, her or living a poly life. I hope it doesn't come to that as I'm a fan of everyone getting their "happily ever after". But I suppose that's a choice that can be put off for now. Good luck.
I'd rather be hated for who I am than loved for who I am not.