Cohabitation is the heterosexual, bisexual, and homosexual moving in together of two partners without going through the formalities of legal marriage. Although similar in form and function, cohabitati...Cohabitation is the heterosexual, bisexual, and homosexual moving in together of two partners without going through the formalities of legal marriage. Although similar in form and function, cohabitating couples live differently in many significant day-to-day aspects when compared to married couples. Also, many cohabiting couples eventually choose to marry, but their risk of divorce is higher than among couples that never cohabited.