Feynman's first wife had tuberculosis and died of it in 1945, spending her last months in a sanatorium in Albuquerque while he worked on the Manhattan Project to build the first atom bomb. Feynman wrote to her every day; six weeks before she died, he wrote: 'You are a nice girl. Every time I think of you, I feel good. It must be love. It sounds like a definition of love. It is love. I love you.'
This has great charm. Feynman was widowed when he was 27, and 16 months later, he wrote another letter to his dead wife, which we are told bore the signs of repeated handling, ending: 'My darling wife, I do adore you. I love my wife. My wife is dead. P.S. Please excuse my not mailing this - but I don't know your new address.'
He was too high-spirited, however, to let this tragedy destroy him, and the following year he produced the work that won him the Nobel Prize."
I haven't read the letters, but I did read "Surely You're Joking, Mr.Feynman!: Adventures of a Curious Character", years ago. It is a wonderful book. Go on treat yourself to a copy.