I think that Stoicism would advocate for recognizing that someone else's actions are beyond your control. You control your thoughts of those actions and your reactions to those actions.
But you also control your actions, and so in that way, you could control staying away from the person as much as possible.
In regard to forgiveness, Marcus Aurelius said. “The best way to avenge yourself is to not be like that.”
Similarly, Epictetus said, “Forgive others for their misdeeds over and over again. This gesture fosters inner ease.”
Forgiveness sets you free, regardless of whether you believe they deserved forgiveness or not.
So, recognize what is in your control, distance yourself as much as you can, and forgive for your own sake.