Complex sentence: The children were asleep and all was well, except that he recalled having left the children's bedroom door slightly ajar, and now it stood almost wide open; he pulled it nearly closed again before returning to the restaurant.
Split into simpler sentences: The children were asleep and all was well, except that he recalled having left the children's bedroom door slightly ajar, and now it stood almost wide open. He pulled it nearly closed again before returning to the restaurant.