I have read The Good Soldier .....
and fortunately it is not too long since I found it, as I do for most modernist novels, a bit boring. I don't know about Ford's wife having an affair, but Rhys was Ford's lover, Perhaps that's why Ford helped her out in her writing. Hemingway didn't care much for Ford. If memory serves me correct, Hemingway has a short section on Ford in A Moveable Feast.
Hemingway wasn't mean about Fitzgerald's writing ....
He admired Fitzgerald's writing. He didn't like his drinking or his language puntuated by four-letter words. He couldn't understand how Fitzgerald could behave so abominably and write such a beautiful novel as Gatsby. One of life's paradoxes.