Against all family advice, the young Richard Feynman married his high-school sweetheart Arline, who was very ill with tuberculosis. Sixteen months after her death, Feynman wrote a letter to her, which you can read at the wonderful site Letters of Note. Here is a characteristic excerpt:
It is such a terribly long time since I last wrote to you — almost two years but I know you'll excuse me because you understand how I am, stubborn and realistic; and I thought there was no sense to writing.