Why do relationships end when nobody has done anything wrong?
Because compatibility is not a fixed property of two people — it is a relationship between who they each are at a particular time, and people change on independent schedules. Most relationships end without a villain, and the absence of one makes the ending harder rather than easier.
The ordinary reasons:
Divergent development. Two people who fitted at 25 have each changed by 35, in directions neither chose deliberately. Nothing was betrayed; the fit was.
Incompatible life direction — children, location, career, proximity to family, how to spend money and time. These are not compromises with a middle; someone has a child or does not.
Different needs for closeness and autonomy, which can be negotiated up to a point and not indefinitely.
Accumulated small erosion rather than any event — the slow reduction of attention, curiosity and generosity, noticed only in aggregate.
Timing, which is real: the same two people at different life stages might have worked.
One person changing what they want — which is permitted, and feels like betrayal to the other.
Why a blameless ending is harder to process:
No narrative. Anger organises grief and gives it somewhere to go. Without a wrong, there is only loss.
No lesson. People want to extract a rule that prevents recurrence, and sometimes there is not one.
Doubt persists. "Could it have worked?" has no answer, and the absence of a clear cause invites indefinite revisiting.
Others ask what happened, and "nothing" is not an accepted answer, which creates pressure to manufacture a fault.
Both may still love each other, which is a genuinely painful configuration and one the culture has no script for.
What helps:
Resisting the urge to build a villain, including out of yourself.
Accepting that a relationship can be good and still end. A relationship that lasted ten years and ended was not a ten-year failure.
Allowing grief without justification.
Limiting contact initially, even amicably, since ambiguity prolongs it.
Expecting non-linear recovery.