If the opposite of love and hate is ambivalence then the opposite of caring about someone is not caring at all about them. I know you can’t forget experiences but you can stop letting them affect you again. You can stop feeling the pain of them. It takes time, and will, and effort.
John and I (and everyone) has experienced some truly awful things. Leaving those experiences behind us doesn’t mean forgetting they happened, it means not letting them affect us anymore. Not letting those experiences define us lets us move on and grow.