We are told in the chronicle written by Desclot soon after his time, that Peter was only trapped into cohabiting with his wife by the device which is familiar to readers of Measure for Measure.
It continued among the Albigenses and other dissident sects of the middle ages, among whom it served a double purpose; for their elders were thus not only able to prove their own chastity, but to elude the inquisitors, who were less inclined to suspect a man of the catharism which regarded marriage as the "greater adultery" (maius adulterium) if they found him cohabiting (in appearance at least) with a woman.
However, it is vital cohabiting couples have all of the information they require to reach a properly informed decision.
For example, 33 percent of Caucasian children lived with fathers who were unmarried but cohabiting with another adult.