Feeling sick

The more and more I think about Mitch and him telling me about his porn watching the more I feel sick. I know he's still a great guy. I just feel awful knowing he had been watching that while were dating. Again...the past is the past...but while he was seeing me? I just feel so sick...I honestly feel like I'm going to throw up.... it's awful...I don't know how to forgive him. I don't know how to get over it to make myself feel better...I just hate it...I need to see my therapist...