I hate the term "ethical non-monogamy" not only because of the implication that monogamy is inherently or by default ethical, and that non-monogamy is therefore by default unethical, but also because the aspects of cheating and polygamy in most places where it's practiced that are unethical have absolutely nothing to do with it being non-monogamous and either has everything to do with betrayal of trust and violation of the relationship agreement you entered (for cheating), or it has everything to do with misogyny and how women are often treated as a commodity and property of their husbands instead of fully actualized people (polygamy within a lot of cultures). In either scenario you can find the root problem popping up within totally monogamous relationships. None of this is unique to non-monogamy.
