kicking over the traces

Somerset Maughamの短編小説 "The Colonel's Lady" から引用します。
"I don't deny that I've had a bit of fun now and then. A man wants it. Women are different."

"We only have men's word for that," said Harry Blane, with a faint smile.

"Evie's absolutely the last woman I'd have suspected of kicking over the traces. I mean, she's a very fastidious, reticent woman. What on earth made her write the damned book?"

大佐の方にも不貞の気配を感じた友人から問われて大佐は男は別だなどと都合の良いことを言っています。
"kicking over the traces" も慣用句の様なので調べます。
・The American Heritage Dictionary of Idioms : Break loose from restraint, misbehave. For example, There's always one child who'll kick over the traces as soon as the bell rings. This metaphoric expression alludes to the straps attaching a horse to a vehicle, which the animal sometimes gets a leg over in order to kick more freely and thereby refuse to move forward.

・Longman Dictionary: British English old-fashioned to start behaving badly by refusing to accept any control or rules: But perhaps even misogynists can kick over the traces.

・Cambridge English Dictionary: to behave badly and show no respect for authority