Cohabitation is when people live together in an emotionally- and/or physically-intimate relationship. The term is most frequently applied to couples who are not married.
People may live together for any of a number of reasons. These may include wanting to test compatibility or to establish financial security before marrying. It may also be because they are unable to legally marry, because for example same-sex, interracial or interreligious marriages are not legal or permitted. Other reasons include living with someone before marriage as a way to avoid divorce, a way for polygamists or polyamorists to avoid breaking the law, a way to avoid the higher income taxes paid by some two-income married couples (in the United States), negative effects on pension payments (among older people), philosophical opposition to the institution of marriage and seeing little difference between the commitment to live together and the commitment to marriage. Some individuals may also choose cohabitation because they see their relationships as being private and personal matters, and not to be controlled by political, religious or patriarchal institutions.
Some couples prefer cohabitation because it does not legally commit them for an extended period, and because it is easier to establish and dissolve without the legal costs often associated with a divorce. In some jurisdictions cohabitation can be viewed legally as common-law marriages, either after the duration of a specified period, or the birth of the couple's child, or if the couple consider and behave accordingly as husband and wife. (This helps provide the surviving partner a legal basis for inheriting the deceased's belongings in the event of the death of their cohabiting partner.)
Today, cohabitation is a common pattern among people in the Western world, especially those who desire marriage but whose financial situation temporarily precludes it, or who wish to prepare for what married life will be like before actually getting married, or because they see no benefit or value offered by marriage. More and more couples choose to have long-term relationships without marriage, and cohabit as a permanent arrangement.
Opposition to cohabitation comes mainly from religious groups. Opponents of cohabitation usually argue that living together in this fashion is less stable and hence harmful. According to one argument, the total and unconditional commitment of marriage strengthens a couple's bond and makes the partners feel more secure, more relaxed, and happier than those that have chosen to cohabitation. Opponents of cohabitation commonly cite statistics that indicate that couples who have lived together before marriage are more likely to divorce, and that unhappiness, ill health, poverty, and domestic violence are more common in unmarried couples than in married ones. Cohabitation advocates, in turn, cite limited research that either disproves these claims or indicates that the statistical differences are due to other factors than the fact of cohabitation itself.
In 2001, in the United States 8.2% of couples were calculated to be cohabiting.
In 2005, the U.S. Census Bureau reported 4.85 million cohabiting couples, up more than 1,000 percent from 1960, when there were 439,000 such couples. A 2000 study found that more than half of newlyweds have lived together, at least briefly, before walking down the aisle.
The cohabiting population is inclusive of all ages, but the average cohabiting age group is between 25-34. This is a meaningless statistic however, as the average married population is in this range also.
Some people have claimed that those who live together before marriage can report having less satisfying marriages and have a higher chance of separating. A possible explanation for this trend could be that people who cohabit prior to marriage did so because of apprehension towards commitment, and when, following marriage, marital problems arose (or, for that matter, before marriage, when relationship problems arose during the cohabitation arrangement), this apprehension was more likely to translate into an eventual separation. It should be noted this model cites antecedent apprehension concerning commitment as the cause of increased break ups and cohabitation only as an indicator of such apprehension. Another explanation is that those who choose not to cohabit prior to marriage are often more conservative in their religious views, a mindset that might prevent them from divorcing for religious reasons despite experiencing marital problems no less severe than those encountered by former cohabitants. In addition, the very act of living together may lead to attitudes that make happy marriages more difficult. The findings of one recent study, for example, suggest "there may be less motivation for cohabiting partners to develop their conflict resolution and support skills." (One important exception: cohabiting couples who are already planning to marry each other in the near future have just as good a chance at staying together as couples who don’t live together before marriage).
Half a century ago, it was illegal in every state for adult lovers to live together without being married. Today, on the other hand, just five (5) states (Mississippi, Virginia, Florida, North Dakota and Michigan) still criminalize cohabitation by opposite-sex couples, although anti-cohabitation laws are generally not enforced. Many legal scholars believe that in light of in Lawrence v. Texas, such laws making cohabitation illegal are unconstitutional (North Carolina Superior Court judge Benjamin Alford has struck down the North Carolina law on that basis).