Fred and Betty: Is this the End?
Episode 2: Not Guilty!
Fred: Betty, you've got to believe me! I would never cheat on you Betty!
CHEAT ON
Meaning: if you cheat on somebody, (your husband, wife, boyfriend or girlfriend) you secretly have a sexual or romantic relationship with someone else. (在男女关系上)不忠实,不忠于(妻子或丈夫)
Grammar: This phrasal verb must have an object. You can not separate the verb from its particle.
He cheated on his wife - RIGHT
He cheated on her - RIGHT
He cheated her on - WRONG
He cheated his wife on - WRONG
Example sentence: Juliet finally decided to divorce her husband when she caught him cheating on her with their next-door neighbour.