Rome, 131 B.C. (fr. 6 Malcovati. L)
The Julian marriage laws (nos. 120-123, etc.)
In 18 B.C., the Emperor Augustus turned his attention to social problems at Rome. Extravagance and adultery were widespread. Among the upper classes, marriage was increasingly infrequent and, many couples who did marry failed to produce offspring. Augustus, who hoped thereby to elevate both the morals and the numbers of the upper classes in Rome, and to increase the population of native Italians in Italy, enacted laws to encourage marriage and having children (lex Julia de maritandis ordinibus), including provisions establishing adultery as a crime.
The law against adultery made the offence a crime punishable by exile and confiscation of property. Fathers were permitted to kill daughters and their partners in adultery. Husbands could kill the partners under certain circumstances and were required to divorce adulterous wives. Augustus himself was obliged to invoke the law against his own daughter, Julia, and relegated her to the island of Pandateria. 
The Augustan social laws were badly received and were modified in A.D. 9 by the lex Papia Poppaea, named for the two bachelor consuls of that year. The earlier and later laws are often referred to in juristic sources as the lex Julia et Papia.
In part as a result of Christian opposition to such policies, the laws were eventually nearly all repealed or fell into disuse under Constantine and later emperors, including the emperor Justinian. Only the prohibitions against intermarriage, as that between senators and actresses, remained.
The first three of the texts that follow do not come from the Roman jurists but give background for the passing of the laws. The remaining texts in this section are from legal works interpreting the provisions of this legislation by a number of jurists. The juristic sources are also our best source for the actual provisions of the laws.
Speech of the censor Quintus Caecilius Metellus Macedonicus  about the law requiring men to marry in order to produce children. According to Livy (Per. 59), in 17 B.C. Augustus read out this speech, which seemed “written for the hour”, in the Senate in support of his own legislation encouraging marriage and childbearing (see no. 121).
If we could survive without a wife, citizens of Rome, all of us would do without that nuisance; but since nature has so decreed that we cannot manage comfortably with them, nor live in any way without them,  we must plan for our lasting preservation rather than for our temporary pleasure.
15. For an interesting fictional account of Julia’s exile and the events which led to it, see [Williams, 1972 #137].
16. This portion of the speech is preserved by Aulus Gellius (1.6.2), who mistakes this Metellus (Macedonicus, cos. 143 B.C.) for Metellus Numidicus (cos. 109 B.C.). Cf. [Holford-Strevens, 1988 #116], 65 n.20, 228.
17. Cf. Aristophanes, Lysistrata 1038-39: ‘A true saying and well-said: you can’t live with the cursed creatures or without them’.