fall out with somebody meaning

 In the late 1980s, his flamboyant tastes and deep fashion knowledge caught the eye of Ms. Wintour, for whom Mr. Talley became adviser, friend and foil, a link to an older, more romantic, less corporate and less bottom-line-oriented age. He even advised Ms. Wintour on her Met Gala outfits.

“What I recall is that I was not so much his protector,” Ms. Wintour said in the documentary. “My fashion history is not so great, and his is impeccable, so I think I learned a lot from him.”

After “The Chiffon Trenches” was published, Mr. Talley fell out with Ms. Wintour, whom he accused of abandoning him. (In the memoir, he suggested that she had played a somewhat parasitic role in his life, feeding off this energy.)

to argue with someone and stop being friendly with them: He left home after falling out with his parents. She'd fallen out with her boyfriend over his ex-girlfriend. Thesaurus: synonyms, antonyms, and examples. to argue with someone.

FALL OUT | English meaning - Cambridge Dictionary