Of all the questions asked on websites or in other publications about personality type, this is probably the most common. It's certainly the one I've seen the most! There seem to be almost as many supposed type - related keys to a successful marriage as there are type preferences. For instance some people say Introverted and Extraverted types are best together. Others say that two people should have the same middle two letters and that their other two letters should be opposites, as in the pairing of INFJ and ENFP.