Why Is It Prohibited for a Muslim to Have a Relationship Outside Marriage?

In the Islamic faith, relationships between men and women outside marriage are not permissible. The Quran clearly states that sexual relations should only take place within the bounds of a legitimate marriage. This rule is meant to protect both individuals involved by ensuring they treat each other honorably. Islam also prohibits any extramarital or premarital sexual intercourse that may lead to unwanted situations such as unplanned pregnancies, sexually transmitted diseases, or emotionally unfulfilling relationships. Muslims believe in creating a family based on mutual love, peace, and security within the confines of strong moral values. 

Islam prohibits sex before marriage because it places great importance on purity and chastity in order to maintain healthy societal norms. Moral values that prohibit such types of conduct are an important part for the formation of a harmonious society where ethical values are given preference over personal desires.