First:
aren't you an ISTJ? is that match even possible?
XD - this comment made me laugh - I'm an INFJ w/an ISTJ, and so far it's been infinitely better than my previous relationships with an ENFP and the ENTP I dated before that. (No offense, they're both great personality types, but there's a LOT that makes being with an ISTJ better in a different way)
Any survival tips? Are we already doomed?
If you (as an INFJ or NF) would move in with an ISTJ (or SJ), what would be the most likely reason for it not to work? What irritates you about us?
As we are both I and J, we both acknowledge each other's need for quiet and stable time at home (= no guys @ 11pm coming to watch a football match without a notice).
But what about me being a ST and she being NF? I already noticed I'm way more pragmatic than she is...
There's going to be a lot of give and take, at least such has been my experience.
Trust her intuition. The average ISTJ doesn't quite understand Ni (then again, I don't understand it all the time) however, it is usually right - so trust it (and the INFJ) At the same time, the INFJ needs to make an effort to quantify *why* they intuitively feel a certain way. My dad is an ISTJ engineer and I've had many many years to learn how to explain my gut feelings.
Your INFJ needs to learn to be somewhat pragmatic - and you need to keep in mind that not everything has to be pragmatic
This might be unique to my relationship, but (I think anyway) because ISTJ's have Fi you're not usually comfortable discussing your innermost feelings; But I'm an INFJ, so I'm usually pretty good at instinctively knowing what a person is feeling. So there have been a couple times where I've had to sit down with with my ISTJ and pull out exactly what she's feeling and why, and what's wrong - I'm just glad she trusts me enough to let me do that.
So as long as you're okay with your INFJ digging into the deep recesses of that great big heart you ISTJ's are so good at keeping hidden and protected, I think you'll be fine ^_^
House keeping wise, I've seen tremendous variance in ISTJ and INFJ living styles - extremes at both end of the spectrum. The ISTJ's I've known are creatures of habit, so as long as your habits aren't difficult to live with it shouldn't be an issue.