A question on Cohabitation My question is regarding cohabitation of man and women prior marriage. 

According to the Catholic Church what is the formal position on this? Acceptable or not?

References would be much appreciated.

Also interested in the Anglican perspective.

Also, if an unmarried (or married) women was cohabiting with unmarried men (not engaging in sexual acts but mearly residing with them for a time)...what would be the Catholic position on this? (This hypothetical scenario vice versa also).
Concubinage/cohabitation is a sin because, among other reasons, it


belittles the sacrament of marriage.
gives scandal.
places one in the occasion of sin to fornicate.


cf. McHugh &amp; Callan's Moral Theology "2527. Forms of Fornication." (c):


  (c) Free love is fornication committed with one's concubine, that is, with a woman who is not a public harlot but who has contracted with one man for habitual sexual intercourse as if they were man and wife. According to reports, this is quite common in Europe, where lawful marriage is very often preceded by free unions. The trial marriage advocated by some in this country, in which paramours agree to live together as husband and wife for a certain term of years or at pleasure, also falls under the category of concubinage. This sin is worse than mere whoremongering in one respect, namely, that it includes the purpose to continue in the state of sin, at least for a certain length of time. Moreover, there is often the public scandal and contempt for public opinion which other kinds of fornication may be free from. One who practises concubinage is living in a proximate occasion of sin, and hence he cannot be absolved unless he dismisses the concubine, if they cohabit, or agrees to keep away from her, if they do not cohabit.