The dual of INFP is not ESTP but ESTJ. INFPs and ESTJs have all the same functions only in different order. This pattern of functions is what forms relations known as duality:
INFP: Fi-Ne-Si-Te
ESTJ: Te-Si-Ne-Fi
How this works is that each personality type actually desires and values some expression of tertiary and inferior functions. But you get exhausted if you have to supply it for yourself, because you draw most of your energy/enjoyment of life from exercising your dominant and auxiliary functions. However if you are in company of another personality that is dominant or auxiliary in these functions then they can supply these for you. This makes you value each other. At the same time having all functions in common yields similar approaches to life and similar ways of making judgements, which increases potential for understanding and decreases potential for conflict.
Overall people prefer to marry somebody who is alike them rather than pair up with their opposites as many studies have demonstrated. According to this article among opposites attract relations ESTJ-INFP and ESTP-INFJ pairings are ones that are most common (these are two dual pairs): Compatibility and Your Myers Briggs Personality Type | PersonalityDesk
INFP: Fi-Ne-Si-Te
ESTJ: Te-Si-Ne-Fi
How this works is that each personality type actually desires and values some expression of tertiary and inferior functions. But you get exhausted if you have to supply it for yourself, because you draw most of your energy/enjoyment of life from exercising your dominant and auxiliary functions. However if you are in company of another personality that is dominant or auxiliary in these functions then they can supply these for you. This makes you value each other. At the same time having all functions in common yields similar approaches to life and similar ways of making judgements, which increases potential for understanding and decreases potential for conflict.
Overall people prefer to marry somebody who is alike them rather than pair up with their opposites as many studies have demonstrated. According to this article among opposites attract relations ESTJ-INFP and ESTP-INFJ pairings are ones that are most common (these are two dual pairs): Compatibility and Your Myers Briggs Personality Type | PersonalityDesk
