It’s never going to be clear why certain people do certain things. The only apparent reason is that they do it because that’s what they are used to. Their subconscious controls them and they do certain things, albeit wrong in our views.
The way to cope is to make sure that we stay as far as possible from these individuals. Have clear boundaries, so they cannot do wrong again. Then, forgive these beings.
Once we are able to forgive them, we then have to let go of the past. Innerstand that these individuals have come to better us, to add to our experiences, innerstand that we needed these beings, for our soul growth. That, we needed to balance Karma with them.
Then, let go. Cut energetic cords. See how much better your life is, for having them on this walk. Thank the path, thank the soul for their teachings. Even if you won’t have them in your life. The lesson is complete.