He has nothing to be ashamed of or to be forgiven for. He had a life where he was learning and growing and now he is the great person you love and adore. Judgment of our lover’s pasts or of our importance based on our comparative insecurities isn’t fair to them. He isn’t with them. He also isn’t hiding anything or trying to be someone he isn’t. Your insecurity is something in you that you need to excavate. Why are you feeling inferior? What is it about you that you think is lacking? Fear of his past will change you into someone you no longer recognize and he cannot respect.