This is NOT your fault, he wants you to believe that and other people who say that are colluding with him. This is how abusers work.

You have a coworker who told you about his being registered as a sex offender, could you confide in this worker? You need to tell someone, this can't go on and as Rohag suggested get some legal advice.

Please believe me, a total stranger, thousands of miles away, this is in no way, shape or form your fault.