In 2002, Ashcroft vs Free Speech Coalition (535 US 234) established that computer generated images could not be classified as illegal ********** in the United States.
Therapists where I live in the US are required to report if a patient tells them they've viewed **********. How this rule interacts with the above holding I don't know. Regardless, I would not rely on a therapist understanding the legal nuance.
I do think the reporting rule is very unfortunate as it prevents people from seeking treatment. The best suggestion I can give is to seek support by discussing the issue with someone you trust.