I have to go with the philosophy that although in therapy it may not seem like it, Therapists are people too and PEOPLE have down falls. They are not perfect. They are not saints.

He doesn't owe you an explanation of whether the sites were his or not. In all honesty it doesn't really matter. As long as his down falls do not effect your future therapeutic relationship with him. Every T from dawn to dusk has their own lives outside of therapy and when we get a glimpse of them, it's scary and overwhelming. Even "unsafe" feeling.

In the grand scheme of things I think you need to tell him WHY him( or anyone you need to trust) having a porn addiction/ or watching porn may effect you.

i.e because my father was a porn addict and I could not trust him.

If your father was a cigar smoker and you found out T smoked cigars... would that be hard to deal with?

For me my abuser was an alcoholic, and I freeze if I come near a drunk person. One day I saw a picture of my T holding a beer and it really effected me. I even considered that my therapist was a drunk because of one beer. Which made me think he was unsafe. T let me know that occasionally he may drink a beer when he is with his brothers from out of town. Seeing this side of him made me scared, but I worked through it. Since then I have met many alcoholics who are NOT bad people, in treatment and so fourth. And when they are not actively drunk I am able to trust them.

Alcohol, cigars, sex is part of many people's lives. And not always in large quantities. And it's okay to be scared, but don't run away because you are. That's only part of a dangerous game you'll continue to play.