- 女性は30歳を過ぎると、どうも年齢を気にせずにはいられないなる。After the age of 30, women can't help but care about their age.
- 二時間も待たされて、担当スタッフに文句を言わずにはいられなかった。After waiting for two hours, I couldn't help but complain to the staff in charge.
- 彼は自分のことを放っておいてでも苦境にいる友だちを助けないではいられない人だ。He, even if he doesn't care about his own affairs, can't help but help his friends in trouble.
It means that you can't control the mood of doing something. If you don't do something, you will feel very uncomfortable.