小三 (xiǎo sān) - third party (mistress)
出轨 (chū guǐ) - to have an affair
绿帽子 (lǜ mào zi) - green hat (Chinese slang for a man who has been cheated on by his partner)
二奶 (èr nǎi) - second wife (Chinese slang for a mistress)
So, the English equivalents would be:
- Third party (mistress)
- To have an affair
- Green hat (slang for a man who has been cheated on)
- Second wife (slang for a mistress)
