Polyamorous relationships exist when at least one partner in a relationship has additional partners. Consider the following hypothetical arrangement:
- Person A is married to Person B.
- Person B has a romantic relationship with Person C.
- Person C is married to Person D.
- People C and D have other partners. (They are omitted in the rest of the question for brevity).
Some states have laws against these kinds of relationships. As an example from the web, Kansas law says:
Adultery. (a) Adultery is engaging in sexual intercourse or sodomy with a person who is not married to the offender if:
(1) The offender is married; or
(2) the offender is not married and knows that the other person involved in the act is married.
(b) Adultery is a class C misdemeanor.
(Source: KSA 21-5511)
Under that law, it would seem that People B and C are likely committing adultery.
Partners in this kind of relationship are subject to certain legal risks. For example, should the relationship between C and D sour, B may be accused of adultery.
Is there any legal "thing" that can help people in polyamorous relationships protect themselves from legal risks arising from their relationships? For example, could they construct a contract or MOU which outlines their mutual expectations that they will have other partners?