Mm3,
I don't log in very often anymore, but I did today, and saw that your ex has taken up with a new woman. You're smart to decide not to waste energy on her decisions. My trans-identifying ex, after deciding to stay closeted, also took up with a new woman. I did tell her, because if it were me, I would want to know--at one point, after all, it was me, and I would have liked to know! It was a futile gesture, and it's very likely anything you said to your ex's new partner wouldn't change her mind.