Good for you. I came to the conclusion that when someone does something ill to another person, it shows what she is capable of and her true character. I learned to tell myself:

"If she could do it to one human being, she could do it to me also if things were to turn sour between us. Don't think that I am an exception."

You make a great point that toxic people is irritated when you start to become more assertive. Well, their reaction reveals their true colors all the more!

Sending you a high-five and a hug.