THis is sad. If he gets help alone, his odds of leaving you are higher than if you seek help as a couple. Things certainly don't always work out, but couseling together typically helps both people understand and accept the direction things are going, regardless of outcome.
You did not answer my question. about communicating with the other person. Why would he continue.
Because he is not willing to cut contact with her. Sorry, I did not see that part of question.That fact should tell you which direction this is heading.