Well, as you say, it looks like karma.
But try not to be too hard on her ~ it won't help you, and, as we have said before, she is very young and has endured some awful experiences.
When she is older, she may realise how thoughtless she was with you.
It is often the way. She may not even realise until she has sons or grandsons of her own.
Meanwhile, stay positive and you will meet your 'Miss Right'.