Any type can get along with any other type, given enough communication and sufficient maturity. People are individuals, not types. MBTI is meant to help people communicate with one another, grow and develop, and not as limitations. However, purely based on types/cognitive functions, these are some issues that may crop up:
ENTP functions: Ne - Ti - Fe - Si
INFP functions: Fi - Ne - Si - Te
You both have Ne and gather information and communicate the same way. The biggest issue is between Fi vs Ti, and in romantic relationships, Fi vs Fe.
Ti finds Fi difficult to comprehend. We rarely make decisions based on deep feelings and values, and find it hard to grasp what Fi is, let alone respect it. Unless the ENTP worked on themself to overcome this bias, there could be a tendency to discount Fi as irrational and meaningless.
For romantic relationships, ENTP express emotions through Fe. We show feelings by facial expression, words, widely-understood loving gestures, and looks for the same kind of response minute-by-minute, in the way you speak, the words you use, the tone. And Fi is famous for being internal, not necessarily expressive—which can leave the Fe in insecurity and anxiety, trying to guess what your feelings are.
This is the biggest difficulty between ENTP and INFP in a relationship: ENTP’s Fe doesn’t understand that feelings can remain constant even without being expressed. We cannot sense INFP feelings easily, or all the time. Worse, some INFP present as very accommodating and easygoing, not expressing their feelings of being offended, until the feelings build up so much they explode out. So for us, it can feel like—INFPs accept us the way we are, so we behave as normal, then suddenly, BAM, for some reason the INFP are now hurt and furious.
Further, because we cannot gauge INFP feelings, our dominant functions—Ne and Ti—do what they always do to gain greater understanding. This is where ENTPs begin to constantly push the INFP’s boundaries, testing them, poking into them, arguing with them, trying to get a visible response so we could understand what their feelings are, what they are feeling/thinking about us.
Immature ENTPs can become very hurtful and insensitive in this way. Mature ENTPs, with more developed Fe, will be much more careful and caring. However, because Fe doesn’t really understand Fi, it might lead the ENTP to tiptoe around Fi, like stepping on eggshells.
Personally, I get along with INFP very well when (1) they have kindness and emotional resilience as their values, and (2) when they have well-developed Ne. Even so, I do tend to tiptoe around until I have a better feel for their values and boundaries.
What I deeply appreciate about INFPs, though, is how warm, even fierce, their feelings can be. They bring out my feeling side, and when our values align, the relationship is fantastic, we help each other grow so much, and the Ne is so much fun