Interpersonal relationship
Non-formalized intimate relationships or long-term relationships such as loving relationships or romantic relationships with or without living together; the other person is often called lover, boyfriend or girlfriend (not to be confused with just a male or female friend). If the partners live together, the relationship may be similar to marriage, and the other person may be called husband or wife. Long term cohabiting relationships are often called common-law marriages, but in the vast majority of the world there is no such legal status. Mistress is the term for a female lover of a man who is married to another woman. She may even be an official mistress (in French maîtresse en titre); an example is Madame de Pompadour.