A relationship whose partners agree that defined sexual and/or romantic connections outside it are permitted.
Sources and evidence type
Manual claim and limitation notes are shown where an individual source audit is complete. Other evidence-type labels are a publisher aid awaiting source-by-source confirmation.
Rubel & Bogaert (2015), CNM relationship-quality reviewResearch study
Source design
Peer-reviewed research or review
What it can support
The specific population, measures and findings reported by the paper.
Important limitation
It cannot automatically establish UK prevalence, causation, diagnosis, consent or an individual outcome. Check recruitment, definitions and study design.
The specific population, measures and findings reported by the paper.
Important limitation
It cannot automatically establish UK prevalence, causation, diagnosis, consent or an individual outcome. Check recruitment, definitions and study design.
The specific population, measures and findings reported by the paper.
Important limitation
It cannot automatically establish UK prevalence, causation, diagnosis, consent or an individual outcome. Check recruitment, definitions and study design.
Illustration created using generative AI; not documentary evidence.
In brief
A negotiated form of openness—not unrestricted access.
Open relationship is a broad everyday label rather than one standard arrangement. Some agreements permit outside sexual contact but reserve romantic commitment; others are more flexible. The content, disclosure and safer-sex terms must be learned from the people involved, not inferred from the label.
Define openness
Partners may discuss people, places, activities, overnights, emotional involvement, disclosure, barriers and testing. Vague permission can leave incompatible assumptions hidden.
The outside partner also needs accurate information relevant to their consent. Privacy does not justify deliberate deception about material health or relationship facts.
Status
Detailed editorial draft
Publisher
The UK Kink Guide
Reviewed
Structured draft present; individual review date not recorded
Evidence
3 cited sources · types labelled below
Jurisdiction
UK-focused general education
Read the rest: evidence, law, safety and sources
Open relationship
A partnered relationship with agreed permission for some outside connections.
Polyamory
CNM commonly open to multiple loving or emotionally significant relationships.
Swinging
Consensual sexual socialising often organised around couples and shared settings.
Don't ask, don't tell
An agreement limiting disclosure; it differs from concealment that breaches an uninformed partner's expectations.
Agreement and autonomy
An open agreement is not permanent and cannot be forced to save a relationship. Reluctant compliance under threat of abandonment deserves attention to freedom and compatibility.
Each person can decline individual encounters. Being open does not turn availability into a relationship duty.
Jealousy and communication
Jealousy may signal fear, insecurity, unmet needs or a valued bond; it is not proof that openness has failed. Compersion is likewise optional.
Communication should address concrete needs without making one person responsible for eliminating every difficult emotion before others act.
Evidence limits
Studies often combine diverse open arrangements or recruit from CNM communities, limiting causal conclusions. Some within-CNM comparisons report differences, but selection and agreement quality may contribute.
Assess the functioning of the actual relationship: consent, honesty, safety, care and whether agreements remain workable.
Non-graphic examples
What the umbrella may include
Partners permit outside dates but discuss overnight stays first.
A couple agrees on barrier and testing practices.
Someone tells a prospective partner the relationship is open.
An agreement allows privacy without requiring false statements.
Partners return to monogamy only through a new mutual decision.
Prepare for an appointment
Questions you could ask a professional
What information would help you understand my question?
What are the realistic options and uncertainties?
How can disability, communication or privacy needs be accommodated?
When should the situation be reviewed again?
These prompts do not replace assessment and do not imply that every reader needs professional care.
Continue learning
Take the next step from definition to context.
Continue with independent guidance connecting open relationship to evidence, consent, safety, uncertainty and practical decisions.
The UK Kink GuideEvidence-led glossary