Okay, okay, I exaggerate. Although I personally have never born witness to the fabled INFJ-INFJ pairing, it is, of course, a possibility; this is evidenced by the fact that we have received more than a few inquiries about the prospective compatibility of such a relationship. On a theoretical level it can work.
A shared strength of intuition and a love of communicating their theories with others means that the INFJs will greatly enjoy doing what they love to do together with each other. This makes them particularly well equipped to help meet the needs of their partner, intuitively knowing and understanding what the other is looking for.
Because INFJs often feel so misunderstood and alien in the world, partnering with someone who understands them so well just as they understand others is likely to be a source of great comfort and friendship.
In addition, INFJs are incredibly good communicators and are very much at home in the realm of relationships.
They really invest Infj dating another infj their relationships and are constantly communicating with their partners in order to troubleshoot any relational issues that might come up. In that way they have a great advantage over other types when it comes to the likelihood of success; by naturally making the relationship a priority and being willing, excited even, to talk about the health of the relationship, they position themselves ahead of other couples from the starting gate.
In other words, the relationship is not likely to suffer from neglect. INFJs are incredibly committed to their theories and ideals. If both INFJ partners see things the same way then there is no problem.
INFJs have a history of Infj dating another infj lofty ideals onto their partners, whatever the type, ultimately resulting in their being accused of having unattainable or unreasonable standards when those ideals fail to be met. And this behavior has been the culprit behind many a failed INFJ relationship.
And they expect a lot. They may fail to consistently enact their own theories or advice. In other words, if one or both of the INFJ partners is looking to the other to complete the Se piece of the equation that they lack, the relationship can and likely will fail.
This is where learning to let go of S outcomes, along with showing grace is extremely important. Both INFJs must understand that they share the same strengths, but along with that comes the same weaknesses.
They cannot expect their partner to pick up where they fail. This may cover everything from finances and budgeting to other pragmatic concerns like remembering to have the car serviced or bills paid on "Infj dating another infj." A final word of caution: INFJs already intuitively know that, generally speaking, the world undervalues their special brand of know-how.
And they often feel undervalued, having to fight hard to get their piece of the proverbial pie and do it authentically.