Complex sentence: Ahmet's success with Bobby Darin after Herb's repeated failures was the last straw for Herb, who left Atlantic Records in 1958, selling his stake in the company to now ex-wife Miriam Bienstock (who married music publisher Freddy Bienstock) and Nesuhi Ertegün.
Split into simpler sentences: Ahmet's success with Bobby Darin after Abramson's repeated failures was the last straw. He left Atlantic Records in 1958, selling his stake in the company to now ex-wife Miriam Bienstock (who married music publisher Freddy Bienstock) and Nesuhi Ertegün.