under the same roof 同在一个屋檐下；同一所房子里

【例句】
They still lived under the same roof but they acted like two strangers.
他们还是同在一个屋檐下生活，但是他们的行为却有如陌路。

They could no longer bear to live under the same roof.
他们再也不能忍受居住在同一所房子里了。