falling-out

村上春樹の短編集の中の 'Thailand' から引用します。
In Bangkok, Satsuki stayed mainly with her Detroit friends. Those were the ones she felt most comfortable with. She had worked at the university hospital in Detroit for almost ten years, researching the immune function of the thyroid gland. Eventually she had had a falling-out with her securities analyst husband, whose dependency on alcohol had grown worse year by year, in addition to which he had become involved with another woman - someone Satsuki knew well.
Satsukiと夫の二人の仲がうまくいっていない文脈からして "falling-out" は口論かあるいは別れることを意味しているのだろうと推測して辞書を見ます。
・Oxford English Dictionary: A quarrel or disagreement.: She told several New York newspapers that her fiance has been falsely accused, calling it a, quote, ‘personal vendetta,’ adding that the two had a falling-out at work.
・Cambridge English Dictionary: an argument: Rachel and Fi had a falling-out and now they're not speaking to each other.
口論の喧嘩で、離婚の意味ではないですね。