how to speak in english---“第三者”?

1.THE THRID PERSON (IN THE RELATIONSHIP)

2.HIS/HER LOVER

3.THE PERSON HE/HER IS HAVING AN AFFAIR WITH

楼上说的根本听不懂,,口语对话里没人那么说

我是海外华人,相信我

paramour

the third one

Third party

the other man/woman

感性森林对