Is it illegal for an unmarried husband to live with a mistress?

Legal subjectivity:

A husband and mistress living together in the name of husband and wife are suspected of bigamy. Whoever constitutes bigamy shall be sentenced to fixed-term imprisonment of not more than two years or criminal detention. Subjectively, this crime shows direct intention, and the motive does not affect the establishment of this crime. If you marry someone knowing that they have a spouse, or if you have a spouse and deliberately marry someone else, it constitutes bigamy.

Legal objectivity:

Article 3 of the Criminal Law of People's Republic of China (PRC) clearly stipulates that it is a crime, and it is convicted and punished according to law; If the law does not clearly stipulate that it is a criminal act, it shall not be convicted and punished. The severity of the penalty in Article 5 of the Criminal Law of People's Republic of China (PRC) shall be commensurate with the crimes committed and the criminal responsibilities assumed by the criminals. Article 258 of the Criminal Law of People's Republic of China (PRC) stipulates that a person who has a spouse commits bigamy or marries another person knowing that he has a spouse shall be sentenced to fixed-term imprisonment of not more than two years or criminal detention.