He had the cheek to ask his ex-girlfriend to babysit for them.

他竟厚着脸皮要他以前的女朋友为他们临时照看小孩。

《牛津词典》

It will get your mind off of your girlfriend, I mean your ex-girlfriend.

它会让你忘记你女朋友，我指的是你前女朋友。

youdao

It reminds me of my ex-girlfriend.

那会让我想起我的前女友。

youdao

For those of you who are on the run from the FBI, your Visa has run out, or you're sitting next to your ex-girlfriend, now would be a good time to put a paper bag over your head.

被FBI通缉的,签证失效的,还有前女友就坐在旁边的,赶快找个纸袋子把脸给蒙上

耶鲁公开课 - 博弈论课程节选

Mr Roe was walking home from a night out and walked past his ex girlfriend's house and sat on the wall outside.

BBC: Ross McIntyre faces jail for attack on Christopher Roe

And while in your haze of tears and shots of Bacardi Limon, it may seem perfectly justified to post a photo of your ex-girlfriend on the toilet, or of your ex-boyfriend measuring his willy, it could potentially land you in jail someday.

FORBES: Newsflash: Posting Naked Pics On Facebook Could Get You In Trouble!

Nor were the allegations supported by any evidence other than the word of the ex-girlfriend.

WSJ: Judith Grossman: A Mother, a Feminist, Aghast