fe.settings:getUserBoardSettings - non array given[AM] - Endchan Magrathea
 >>/33857/
Something occurred to me just recently, the biggest problem in ego and ego's anima/us relationship is not the sudden loss of attraction, it's not like you'll suddenly start to hate the person that is yourself (unless you have some unresolved issues with your own self). What breaks the deal is that fears and insecurities of both persons latch onto and double on one another just as the functions in their egos cling to and reinforce one another. 
Example: INFJ (Ni Fe Ti Se) and ENFP (Ne Fi Te Si)
Since fears, insecurities and inadequacies are in the shadow/anima it follows that through Ne nemesis INFJ fears of what others want (might manifest as desire not to force anyone into anything or straight up paranoia), ENFP in turn fears their own wants/will. INFJ will seek to confirm what ENFP wants and will find absolutely nothing there leading to the next issue. INFJ's Fi critic renders them unable to act on their own whims/what they feel like doing unless they have external justification. They might be okay with bending ENFP to their own will for a bit but soon they'll doubt their motivations, their sense of moral worth for literally forcing their will onto another human being, especially one that desires freedom as much as ENFP, and they'll meet with ENFP's Fe critic which looks down on other people's motivations. Big oof. 
Next step is INFJ trying to justify themselves with logic but that comes out as rationalization through Te trickster which fumbles all the time leading to misunderstandings in turn multiplied by ENFP's Ti trickster wrongly seeing logical consistency where there is none or failing to see one where there is.
I don't fully understand how Se and Si demons would interact so I'll stop here. What I've outlined above is catastrophe enough. There's a multitude of scenarios like that since each of the functions is responsible for several things (Ni facilitates wants, decisiveness, willpower, structuring one's own future, recognition of patterns leading to specific consequences, and - although I doubt any experiment to confirm this will ever be carried out - luck). To sum up ego-ego's shadow relationship is something that works good when everything is good but falls apart when life goes through a darker patch.
The solution to INFJ's shadow is INTJ and it works both ways. INTJ will probably make their wants clear to INFJ before they start worrying about them. Fi critic won't meet with Ti critic face to face, for INFJ it will be adressed by INTJ's Fi child which judges others' worth honestly and innocently. Same with Ti child reassuring Ti critic when INTJ doubts their plans. Te trickster will be mercifully pardoned by Te parent because it genuinely understands, and Fe parent will know that Fe trickster doesn't mean ill even if what it says comes out hurtful or selfish because Fe parent is empathy.

I could address each potential pairing but it would take several walls of text. People either marry one of their own personalities (which I'd guess only lasts until they mature and master that personality), one of the personalities of their ideal type (inefficiency, unnecessary misunderstandings, avoidable lifestyle differences you'd have to force yourself to cope with) or they try their luck with introverted/extroverted versions of those personalities when they had bad experiences with the better suited types, or it's either convenient or these are the types present in their lives and they fall to peer pressure/loneliness. Unfortunately, however, every choice other than T/F in one's type switched is wrong and by that I mean it won't stand the test of time (might last until death but not eternity) since it's not a true perpetuum mobile that's going to give out more energy than than gets put into it. That and when you marry someone not of your perfect type you take away the chance for person who's perfect for them to join their lives and be happy with them rather than be content at best like you would. It's bad for everyone.