i've been with him for 5 years, and I have been up and down, I have decided that I am going to be my whole Extreme ENFP self and not hide it. Sure, I do want to develop my Te, which is what I do admire in him. But you're absolutely right, being raised in an ISTJ culture definitely has helped him develop some skewed point of views. I do have a hard time fitting in with his family... We are much more successful working on our ENFP and ISTJ relationship when it's just us, when you throw his family into the picture, I think they brainwash him..
2XtremeENFP, in typical P fashion, I never like to say never. Could you be happy with this guy in the longterm? Perhaps. And five years is a big investment to walk away from. But seeing that you could make things work, is not the same as having the optimal relationship to make them work. So there's more to the story here than, "could it work out between me and this ISTJ and his ISTJ family?"
Am I advocating that you dump him just because he's an ISTJ? Absolutely not. But what I am challenging you to do is to take a realllllllly hard look at the facts. Use that Te that you so admire in your boyfriend. Ask yourself if you are willing to put in all the extra work for the next 40-50 years into this relationship to overcome the inherent communications obstacles.
When I say EXTRA WORK I mean in comparison to someone who is on your wavelength.... like any N in general and an NF in particular.
If you don't mind answering, how old are you? How much dating experience have you had? Let me share with you some mistakes I've made: I'm in my late 30s. And, it wasn't until two years ago shortly after my ESFP boyfriend (with his dominant Se) and I broke up, that I FINALLY got HOW DIFFERENT Ss and Ns were. It's not that he and I didn't want the same things in life so much as we didn't speak the same language about the things we wanted.
So if I could share the lesson I've finally learned with others, I'd tell those with dominant S/N functions to be very aware of the communication gap when dating someone with a differing but dominant S/N function.
In my and your case, 2XtremeENFP, we have dominant Intuition (Ne). According to some (see link
here) this means that it is more important for you than people with dominant T/F (like an INFP with dominant Fi, for example) to be with someone who matches your dominant function. In other words, the communication gap is wider for you and other dominant S/N types. You know who else this is true for? ISTJs with their dominant Introverted Sensing. They, too, are happiest with dominant Sensors.... which you are not.
I asked about your dating experience because I can tell you that compared to dating an S, dating an N is like living on a cloud. I was wondering if you've ever experienced this S/N difference in your dating life and how it felt to you? Ns get me. They don't mind when I hop around in the conversation or when I spend hours rambling on about ideas. There is a deep, fulfilling way of communicating among Ns that is not possible with Ss... and especially with dominant Sensors.
You may be attracted to the stability of your ISTJ. But there are Ns that can give you this kind of stability, too. In fact, INTJs and INFJs (and I've seriously dated both) give me that kind of stability and it is very nice.
Your ISTJ may be a great guy. But life is so short and so hard. I've come to the conclusion that while I can't stop fighting battles in life, I can sometimes choose which battles I fight.... I have chosen to not fight the S/N battle with my significant other.
I hope this gives you some insight that will help you while you make your own decisions.