Sociologists study the difference between cohabitation and marriage. Here's one paper that's recently been making the rounds among economists: http://people.k

Sociologists study the difference between cohabitation and marriage. Here's one paper that's recently been making the rounds among economists: http://people.ku.edu/~dginther/working%20papers/Marriage_specialization_man.pdf http://people.ku.edu/~dginther/working%20papers/Marriage_spe...