A more thorough explanation:

Meretricious

In family law, meretricious refers to a relationship where two people live together as if they are married, but without being legally married.

John and Jane have been living together for five years, sharing a home and expenses, but they have never gone through a legal marriage ceremony. They are in a meretricious relationship.

Tom and Sarah have been dating for a few months and have decided to move in together. They are not married, but they will be in a meretricious relationship once they start living together.

Meretricious relationships are similar to common-law marriages, but they are not recognized as legal marriages in all states. In these relationships, the couple lives together and shares expenses, but they do not have the legal rights and protections that come with marriage. The term "meretricious" comes from the Latin word "meretrix," which means "prostitute." This is because in the past, living together without being married was seen as immoral and akin to prostitution. Today, however, many couples choose to live together without getting married, and meretricious relationships are becoming more common.