TS Eliot had a long-term epistolary relationship with Emily Hale, a philosophy teacher, and his 1000 letters to her are now available at Princeton University (the library had to wait 50 years after both their deaths). Here’s an article about the letters.
Another more snarky article recounts the nasty letter Eliot insisted on leaving at the Harvard Library, to be revealed at the same time as the collection. This letter expresses his dismay that his letters were going to be revealed. (He also says, basically, “I never liked her! She was dumb!”)
Now, now, we don’t have to think the poet is a worthy man to admire the poetry.