Interpersonal relationships are dynamic systems that change continuously during their existence. Like living organisms, relationships have a beginning, a lifespan, and an end. They tend to grow and improve gradually, as people get to know each other and become closer emotionally, or they gradually deteriorate as people drift apart and form new relationships with others. One of the most influential models of relationship development was proposed by psychologist, George Levinger. This model was formulated to describe heterosexual, adult romantic relationships, but it has been applied to other kinds of interpersonal relations as well. According to the model, the natural development of a relationship follows five stages:

Legal sanction reinforces and regularizes marriages and civil unions as perceived "respectable" building-blocks of society. In the United States of America, for example, the de-criminalization of homosexual sexual relations in the Supreme Court decision, Lawrence v. Texas (2003) facilitated the mainstreaming of gay long-term relationships, and broached the possibility of the legalization of same-sex marriages in that country.

here