The marital problems between Ronald and Edith were probably linked to Tolkien's nervous breakdown of late 1945 and early 1946 (mostly due to over-work), when he took time off his Professorial duties and lived in a pub with Christopher to seek a better frame of mind.
He was also, at this point, suffering writers' block with Lord of the Rings, and was instead exploring psychological and spiritual issues via the The Notion Club Papers - a projected novel of time travel, loosely based on The Inklings.
I discuss these matters over at the Notion Club Papers blog - also requesting further information from scholars with knowledge of unpublished material.
