Hey everybody,
I admit, I've been following this and other fora and platforms for a while, but just haven't been active much...but I came across this thread and just wanted to get the discussion going again, and to share my perspective.
I'm pretty much a textbook ENTP, although in times of crisis more INTP-like, which is when I know that something's wrong in my life.
I'm a guy in my late twenties, and after two catastrophic relationships with ENTJs, I've been in a relationship with an ENFP for the past year and a half, and we're now engaged.
At this point I want to especially thank [MENTION=15291]Mane[/MENTION] for the comments and insights and also questions which have really been insightful.
I'll go into more detail at a later point, but for now I can confirm that it is really the Fe-Fi nut that's the toughest to crack. Yes, one of the examples discussed has been the difference in how we create our own value systems, but essentially it comes down to something simpler - Fe just means that the focus is on your partner's feelings and that you try to understand and also address his or her feelings in the context of the relationship in order to solve conflicts in a relationship. In fact, for myself, as for many Fe.s I'm sure, I've found it often easier to understand other people's feelings than my own. This being the other way round for an Fi creates several problems, that are intensified in an ENTP-ENFP relationship because it just seems so silly to have these conflicts when you're just so similar in so many other ways.
To give a concrete example, whenever we fight, which happens rather frequently, I prefer to get it out in the open immediately, whereas I get the impression that ENFPs first have a need to take some time for themselves and process some feelings alone before actually being ready to talk about everything, and when they do, they do it solely from their own emotional perspective.
Now, the good news is that with some awareness, this can become a minor problem - if the ENTP has some other Fe close to them, friends or family, that "get them" emotionally. One of my friends is an ENFJ, and while we're not that close because I think we just don't find each other that interesting, at times he's managed to play that role, to make me feel understood, and to "recharge my emotional batteries". Which I really need because I'm surrounded by a lot of Fi.s in my life.
The Ti-Te difference has not been a big issue in my relationship. We have very similar values and principles, although the way we've developed them and the way we defend them is quite different. It seems like ENFP's value sets are more closely linked to their childhood and past experiences. For instance, both me and my ENFP are libertarians. I have rather socially conservative parents, and I've questioned their ideas from an early age on; whereas my ENFP grew up with a quite libertarian mother. We both had issues with our fathers, but they seem to have influenced my ENFP much more than me.
From an ENTP perspective, I think if we date an ENFP, we have to be aware that the Fe-Fi difference means that we just cannot expect certain things to be as (easy or) fulfilling on an emotional level as it would be typically expected to be in a romantic relationship. But the chemistry that comes with the fact that you're so similar but different (I do find the Te in the ENFP quite attractive

) almost guarantee for great times. If you can work through the rest, that is.