Until you meet some of these "willfully blind" people, you have a hard time believing they exist.  Years ago I had a room mate whose boyfriend was such a pig that none of her friends, male or female, could stand to be in the room with him--you see everyone slowly migrate from kitchen to living room.  He had no job and would use her car while she was at work to go have affairs with other willfully blind women.  Then he fixated on a friend of one of her friends and started sending her stalker, creepy, explicit e-mails to which she would reply F-off.  She finally printed them out and showed up at the door and tried to hand them to my room mate saying she needed to see what her so-called boyfriend was up to.  She just looked at the sheaf of paper and walked away.  After he totally spent all her money, he left her for another sucker.  I also met a male version of this type who lost everything.  Intensive counseling only works when the person admits something is wrong.