I do not agree actually. The thing is.. that SLEs do have a similar extreme and enduring nature about them, which makes them perfect for IEIs. The thing is that Ni/Se users often run over Si/Ne users by their pressuring or rather extreme nature, which in my experience makes them incompatible for close relationships. For me it takes my equal (someone with force) to "tame" me and to put me in my place. Something an Si/Ne user often does not want to do, they want 'lax' restrictions. Like for example I had some Delta NFs who were interested in me.. but I knew I had to really control myself with them in a close relationship (which is not very comfortable), like I really feel too 'mean' for such nice and easy going people. An EIE friend said somethign similar.. she gets really mean when people are too submissive (and she always feels sorry afterwards like me).
My SLE best friend told me and I told her that only the two of us can actually convince the other person to do something or make the other person want to do something. SLEs often get bored of consistency, which is very mich provided by Si users and which Ne users seek.
Btw you also bolded the subtle "Fe" part, but SEIs use Fe just as subtly as IEIs, they are Fe creatives as well. Many of them are actually shier than me.. which might be because of my so/sx nature. The thing is even though I am a dreamy and sometimes shy person (depending on the situation and people), I do have a completely different extreme, hard headed and enduring side about me, which is also needed, because we do not break as easily from an SLE pressure, especially males can be 'divas' in a way, the are betas after all.. and they attract a lot of drama like all of us lol.
The thing about the not opening up to that SLE guy for example is that being put in an environment with complete strangers puts me under pressure to act and behave 'normal' or very cautious at first, especially with a potential romantic match.. like I really want to observe people and who the are at first to get an impression of who they are or might be. In a more relaxed environment with friends and soem new people the game usually changes and I actually am pretty capeable of controlling he mood of a whole group as soon as the dynamics are made clear.
Also I feel that the often sexual nature of ESTps is only matched by another Beta, if not an IEI (who are just as sexual beings as ESTps).
Also duality only hits after spending quite a long time together, I never had an as intense bond with another ESTp (even though I do find them extremely attractive), because there was not close interaction. Even after talking to soem it is not enough. You really gotta work together or spend a few hours with them alone. But these were just my two cents.