Well, first of all a relationship is about what two people want. Normally they want to be together. So both make sacrifices in order to make common gains: I want pasta for dinner, I want rice, so let's have couscous. No losers, just winners.
A lot of the time the things we cling so desperately to, in order not to lose them, are meaningless anyway.
Mutual commonality sounds pretty boring. I mean, of course there must be some commonalities, but... It basically sounds like being in a relationship with ones self. Kind of defeats the purpose of being in a relationship really. For me, half the fun and excitement of relationships is a healthy level of push and pull (oooooh-errrrrr).
Anyway, I think you are obfuscating the term compromise with the term capitulation.
With the eye of wisdom we discover a lot of anger in us, any amount of jealousy, resentment, ignorance, desire - mountains of emotion whose existence we would never have suspected in ourselves... We recognize that most of the faults we perceive in others are only the mirror of our own negativity, the reflection of our own disturbed feelings... At the same time, we relieve the world around us of the burden of our own negative judgements."
Gendun Rinpoche Heart Advice from a Mahamudra Master