Relationship is about growth.
We come together in relationship with another for our evolution and growth.
The people you attract are simply mirror manifestations in that moment in time that reflect who you are.
Relationship is really not about the duration that you stay with someone, but the degree to which you both grow, evolve, and become more authentically your true Self.
Staying in a relationship where you are both no longer growing simply because that is the thing to do based on societal standards, or because you made a commitment years ago, is not success.