Love, sex, and marriage in ancient Rome were defined by the patriarchy. The head of the household was the father (the pater familias) who had complete control over the lives of his wife, children, and slaves. This paradigm was justified, in part, by one of the stories related to the foundational myth of Rome in which the demigods Romulus and Remus argue, Romulus kills Remus, and Romulus founds the city of Rome in 753 BCE.
This is a companion discussion topic for the original content at https://www.worldhistory.org/article/1592/love-sex--marriage-in-ancient-rome/.