My girlfriend is an INTJ and I myself am an INFJ. My personal experience has been that we get along extraordinarily well despite the differences. The main difference being that when presented with an issue or conflict, I have to react by feeling first, but as an INFJ I still have to Think about my feelings later and why I feel that way whereas my girlfriend will think about how she feels first, and logically map out a solution to either avoid feeling or resolve any feelings that came about from the issue.

So long as she remembers to be patient while I feel first then catch up later, we can solve any problem set before us. And as long as I remember that she doesn’t really consider other people’s feelings, I can use her logical solution to find a similar one that usually is a win/win/win for all involved.

TL;DR- I am Fi. Girlfriend is Ti. I feel first and think later. She thinks first and feels later. Works very well together when we remember to be patient with the other.