He has a problem. That being said, I'm not sure why THREE affairs wasn't a deal breaker, but internet porn is? Did you think he had completely changed, without getting any treatment for his admitted sexual addiction?
Are you in a position to issue an ultimatum? If so, treatment might save your M. BUT - if you are not financially or otherwise in a position to take the very real chance that he will walk out instead, you may want to bite your tongue until you can get a little emergency fund put away or make some financial plans (see an attorney to see what you would get in temporary support etc.)
