An open relationship is a type of intimate relationship that is sexually non-monogamous. It is an arrangement where one or more parties have permission to be romantically or sexually involved with people outside of the relationship. This is opposed to a traditionally "closed" relationship, where both parties agree to be with one another exclusively. The concept of an open relationship has been recognized since the 1970s.

Open relationships include any type of romantic relationship (dating, marriage, etc.) that is open. There are several different styles of open relationships, including multi-partner relationships, where three or more partners are involved, but a sexual relationship does not occur between all of the parties involved.

The term open relationship is sometimes used interchangeably with the closely related term polyamory, but the two concepts are not identical. The main unifying element to open relationship styles is non-exclusivity of romantic or sexual relationships. Another generic term for all these types of relationships is open love.

If you and your partner are interested in exploring an open relationship, it’s essential that you both agree to rules or best practices. For example, you both may agree to use safe sex practices such as condoms. It’s crucial that you’re both on the same page and stick to the agreements that are made. Sometimes couples engage in therapy to discuss these issues and explore their feelings.

Open relationships require top-notch communication, clear boundaries, and expectations to work. On the surface, an open relationship is one where you and your partner agree to allow sexual encounters with other people. “Open relationships are sometimes referred to as ‘monogamish,’” explains Ashera DeRosa, owner and licensed marriage and family therapist at Whole Stories Therapy, Buffalo, New York. “They fall under the ENM (ethically non-monogamous) umbrella” .

Open relationships can provide variety and excitement, help both partners become skilled at communicating their personal needs, and relieve the pressure of having to fulfill all the emotional and sexual needs of one partner. However, they are not without their pitfalls, especially if boundaries aren’t clear or both partners aren’t as invested in the idea of sexual intimacy with other people.