Most Helpful Guy
Well... you know, dating married men isn't good. I can expect someone to say "slut shaming" in response, but yeah... dating married men is not good. Don't try to rationalize your terrible actions, just don't talk to him again and move on with your life.
Oh, and yeah, he is horrible too for doing what he is doing. He is obviously a man with low moral fiber. Obviously you two selfish buffoons don't care about how you might be hurting his poor wife.
Most Helpful Girl
But not contacting him ever again..
He was already a ruined man when he met you.
That's his karma. Your karma is how you behave.