待小三死后你又去找小四
[dài xiăo sān sĭ hòu nĭ yòu qù zhăo xiăo sì]
This is a rather cynical or satirical nickname, implying the person often has affairs with others. In this context, '小三' ('xiao san') means the third party in a love triangle. '小四' ('xiao si') refers metaphorically to the next one in line after another affair ends. It shows disapproval of infidelity.