The writer is writing a letter to their deceased father to acknowledge that their father was right about many things in the writer's life, even though he never directly said so. The father was correct in his assessments of the writer's romantic relationships, career choices, and decisions, which the writer realized were not actually good choices despite appearing good "on paper." The writer is admitting their father's wisdom and insight, even after his death.

1. Dear Dad, Prince of the Partridge, Purveyor of
Practicalities, King of Birdseye and Sayer of Sooth,
It’s about time I wrote to you. I know you’re gone
and there’s no chance you’ll ever read this, but
since you did me dirty and wrote from the grave,
I figure you owe me one.
You were right. First time for everything, you’d
say, but I’m serious. You were right about me,
about Martin, about my love life in general, and
I’ve finally realized you were right about my
career, too.
Maybe you never came out and said that I was
doing the wrong thing—not directly, anyway—but
you were right about the decisions I was making.
I was following what was “good on paper.”
“Good on paper” sucks in real life.