In The Crucible, why does John Proctor dislike himself?

The main reason John Proctor dislikes himself is because of the affair he had with Abigail.  He feels the shame and embarrassment of a man who knows he has lost his wife’s trust.  During a time when Elizabeth was sick and Abigail was their maid, John and Abigail snuck behind the barn for some “extra-curricular” activities.  Now, Abigail is accusing Elizabeth Proctor of witchcraft in hopes of getting rid of her and claiming John.  John is ashamed of the affair, and now his actions could have dire consequences for Elizabeth and his family.  It takes a while for John to reconcile his responsibility in the matter (he will also be embarrassed if the Salem community finds out about the affair), but he finally does the right thing and confesses to the judges and court about the affair.  Unfortunately, in an attempt to protect her husband, Elizabeth lies to the judges saying that John didn’t have an affair.  Elizabeth’s lie seals his fate.  He is accused of witchcraft and later hanged for his indiscretions and refusal to admit he “trafficked” with the devil.