Because that story was load-bearing.

If Marlowe was the villain, then Desmond was merely unlucky, and his drinking was grief, and his isolation was dignity, and none of the wreckage was his fault.

But if he ever looked — really looked, at the app, at the letters, at the dates — the story would invert, and he would have to become the villain of his own life, the man who threw out his pregnant wife on a lie he could have disproved in thirty seconds.

So he did not look.

For four years he chose, every day, the small comfortable blindness over the enormous unbearable truth.

And Posy grew from a newborn into a child on a dictionary in all the time he spent not looking.