How do therapists manage secondary trauma?

I have always been curious about second hand trauma from therapy because I know that being a therapist is super hard. I know that it is a part of your job to listen to what your clients want to tell you, but I know that it’s a lot, and honestly, there’s a lot of times that I shy away from telling my therapist things because I’m worried about them as a human. What do therapists do when y’all hear traumatic things from clients and how do you manage your own mental health?