The fifth season begins with Sasha proposing some ideas in that period, especially new amendments to Noah's text. On the other hand, there is a new relationship between Sasha and Helen, and Noah notices that relationship, and Bruce enters a bad path, especially as everything gets worse. Meanwhile, there is a new business trip by Joanie, which continues in violent confrontations.
I'd probably follow these characters (even Whitney) for an indefinite number of seasons - partly because of the sucker that I am, but also because "The Affair" can never be completely considered down for the count.
The Affair has always been a fascinating show to watch because much like its characters, it has never feared following its instincts down the wildest paths possible, even if those instincts lead to some terrible choices.