Complex sentence: He begins to gets his drinking under control except for occasional binges, though his marriage begins to come under increasing strain as Eliza's patience with him grows thinner, and by the fifth chapter they are no longer sleeping in the same bedroom.
Split into simpler sentences: He begins to gets his drinking under control, save for occasional binges, though his marriage becomes strained as Eliza's patience with him grows thinner. By the fifth chapter they are no longer sleeping in the same bedroom.