A creeping sense of finitude is ever persistent when you have a child. Particularly, in the first few weeks when you lose complete sense of time.
I came across this poem of his from when he was lot younger.
My son, my executioner, I take you in my arms, Quiet and small and just astir And whom my body warms. Sweet death, small son, our instrument Of immortality, Your cries and hunger document Our bodily decay. We twenty-five and twenty-two Who seemed to live forever Observe enduring life in you And start to die together.