Yeah. I think the reason he never tells Ben and/or Rose isn't because he doesn't trust them to keep it a secret, or that he's worried about people from his past finding him, but because he's violently ashamed. He's probably afraid they won't like him anymore, if they find out.

On the other hand, I think his managing to go sober is directly related to how he was sort of forced out of his denial/repression about his past; I think he's trying really really hard to be a more responsible person and not make the same mistakes.