sentences:  The Williamsons believed their venture was about exchanging partners for sex and setting society free, and that monogamy was sexually unsatisfactory and preventing people from having full lives.The retreat offered members and guests over the age of 18 the resources of a spa with the addition of several large open communal sleeping areas, both indoor and outdoor, and communal bathrooms.Prospective members were interviewed on a daytime visit to determine suitability.