三人行必有我媳妇
[sān rén xíng bì yŏu wŏ xí fù]
Translates to 'In every trio, there must be my wife'. The user may be making fun of themselves or implying a humorous fantasy where the user imagines being part of every group with their spouse or desired companion. Or it could simply reflect their longing to find a relationship within various social circles.