Dear Miss D,
Run, don't walk away from this guy.
He Has To Work Out His Own Problems
I'm not sure what your ultimate goals are or were in this situation, but it's clearly out of hand. For your own protection, and for his own good, you should get away from him. As intelligent as you say he is, he should realize that you were only playing and that he has to work out his own problems.
Go back to your parties, your friends, your fun, and leave this guy to his hang-ups.
You Are Breaking Up His Marriage
Too cold, you say? How about breaking up a marriage?