In The Fiddler on the Roof - Tevye could finally not "bend" any further. What is this referring to?

In context, this directly refers to Tevye's inability to tolerate the marriage of his third daughter to a non-Jew. He bent to tradition when he allowed his two oldest daughters to marry men without the intervention of a matchmaker, but Chava's marriage to an Orthodox Christian was beyond him, and he disowned her, she was "dead to him".