I think both
...novel mentioned
You're not wrong, I think it symbolizes all if it but it's also literal. In the novel is smashes her against the glass and she's covered in cuts and blood from the glass.
I thought it was because she pushed her against it when she started screaming at him...
I thought it was because he pushed her against it when she started screaming at him...
A symbolic representation of that always-calm-and-in-control facade of his cracking, and physically represented by Ruby both being hurt by it and smashing it (that's how I saw it anyways)
So the glass breaking was from his patience cracking or from the fact that he’s losing his power of Ruby?