Parts of relationships I was good at
1. Fairness.
2. Good at understanding other views.
3. Reasonable.
4. Pretty emotionally calm / patient.
5. Good at predicting outcome of choices/behaviors.
Things I was bad at
1. Sharing thoughts/emotions or proactively asking partners about theirs
2. Dismissing value of customs and routines
3. Neglecting opportunities for interdependence in the relationship
4. Not respecting/accommodating partners' emotional needs
5. Could be touchy if I felt pressured by presumed
6. Being proactive to resolve personal conflicts, I typically would try to sidestep or avoid.
The whole "fairness" thing for some people flies in the face of "loyalty." I won't take someone's side just because I'm close to them, if I don't think they are right after I analyze their position. Sometimes that is seen as betrayal.
I do typically view "equality" as important in the relationship, but I found if I'm dealing with someone who is more interested in fighting for their position, then that leaves me at a disadvantage.
I think this is one of the most difficult aspects of having a relationship with an INTP. If you're trying to fix your partner, it's inevitable that you'll be focusing on what you don't like about them. And time spent trying to resolve perceived incompatibilities takes away from time spent simply enjoying your partner's company.
I would see all the flaws in my partner but didn't necessarily want to fix him; it was more like a "live and let live" situation. The flaws were obvious, so I figured my partner saw mine, and we had a tacit agreement to be accepting and reasonable and constructive (in my head).
What got bad is when my partner was trying to fix me when I wasn't trying to fix my partner, and eventually things would come to a head due to the unfairness factor. I would get frustrated at the inequity, and if I was pushed too hard, since I was really aware of my partner's weaknesses, if I decided to take off the gloves, things could get bad.
I think many types of people view their partners as "fix-it" projects.