Complex sentence: Although published under Marthe's name, it is speculated that her husband was largely responsible for their writing, and no further books were forthcoming when the McKennas' marriage ended around 1951.
Split into simpler sentences: Although published under Marthe's name, it is speculated that her husband was largely responsible for their writing. The McKennas later returned to Marthe's family home in Westrozebeke and no further books were forthcoming when the McKennas' marriage ended around 1951.