Your boyfriend would need to see a psychiatrist or psychologist to be diagnosed with narcissistic personality disorder. Based on the little bit of information that you shared here, he may be dealing with guilt, anger, sadness, and regret over his immoral behavior. He may be raging at you because he's mad at himself for breaking up his marriage, disrespecting his sacred vows, and hurting his wife and child. He hasn't behaved in an honorable way and is now living with the consequences.
Those who believe in karma would say that being on the receiving end of his anger is you reaping what you sowed. By having an affair with a married man, you set yourself up for misery. Instead of focusing on whether or not this guy is a narcissist, you'd be much wiser to concentrate on yourself. If you're a good person, you should be dealing with a lot of guilt now. If you're not dealing with guilt, you must ask yourself why you've grown so selfish and callous.
This is a wonderful opportunity for you to end this relationship and get your life back on track. Talking to a counselor or religious leader at church would be extremely beneficial. You need to start doing things that make you proud of yourself and, thus, build your self-esteem. Surround yourself with better people who hold you to higher standards of behavior.