Consensual non-monogamy (CNM). An umbrella term for all kinds of relationship models in which people have more than one sex partner (open relationships). Sometimes this involves more than one romantic partner too (polyamory). The people in these relationships know this is happening and they consent to this. The term ethical non-monogamy (ENM) is also used.

CNM, ethical non-monogamy, ENM, consenting non-monogamy