Deciding to end this sort of a relationship is a sound choice. You cannot rely on only on his words that he loves you. You've looked at the actions and they are contradictory.
Why he is behaving like this can be caused by different things. The fact remains though that he is not admitting wrong doing or trying to correct his behavior. His behavior could be a defense mechanism (he has this sort of an addiction to sex/internet), he is somewhat narcissistic and your confrontation had put him on the defense, the initial dating stage where he tried to charm you is over and you saw other characteristics of his personality. He may also subconsciously be taking his frustration by acting this way onto you (something he may have as an unresolved issue with his ex).