Is there any in-game 'benefit' to building a relationship in the game? I remember in Dragon Age (can't remember which) you were awarded special player synergies, so that was useful. Of course, you need to keep your other party members happy enough to remain (if you want them), that is a given - but the relationship stuff is more often than not something I find a chore...unless there's some reason to pursue it, like a perk that increases your effectiveness....
That should be Dragon Age Origins. If I find no companions in any way interesting, I usually consider that a central failure. E.g. Andromeda, Inquisition to an extent