The research, published in the Journal of Sex Research, was conducted using couples divided into five distinct classes of relationships: two monogamous groups (representing earlier and later stage monogamous relationships); consensual non-monogamous relationships; partially open relationships and one-sided sexual relationships (in which one partner desires monogamy while the other partner engages in sex outside the existing relationship).

The team discovered that monogamous and consensual non-monogamous groups demonstrated high levels of functioning in their relationships and as individuals, whereas the partially open and one-sided non-monogamous groups showed lower functioning levels.

People in both monogamous groups reported relatively healthy relationships, as well as some of the lowest levels of loneliness and psychological distress. Both monogamous groups and the consensual non-monogamous group reported similarly low levels of loneliness and distress, and similarly high satisfaction levels in regards to need, relationship, and sex.

Open relationships: do they work? New research reveals the truth