California's very short because of how non-mono friendly it is, VERY few laws have any affect on non-monogamists. Go golden state!
Non-Monogamous Families and the Law, Part 4: Summary of California Laws
California has no laws regarding adultery, and as such is very non-monogamous friendly. This absence makes the state very friendly to swingers and open relationship families in particular.
California does possess bigamy laws; however, they lack the trappings of other states, for example a lack of co-habitation and/or purportation clauses in the bigamy laws (California State Legislature, 2011a). The simplicity of California bigamy laws makes for a relatively safer environment for non-monogamists. Strangely absent are solicitation, conspiracy and attempt laws that affect bigamy. This absence removes yet another level of liability for non-monogamists.
Despite this, in the event that there is a legal multi-partner marriage (and not just the appearance of such), Bigamy is still considered a criminal offence and is subject to up to one year of jail time and a fine between $5,000 and $10,000 (California State Legislature, 2011b; California State Legislature, 2101c). Liability for bigamy extends not only to the bigamous partner, but also to the partner being married in to the family, provided this person knows of the arrangement (California State Legislature, 2011c).
Cross-Relation between the Laws:
Due to the absence of adultery laws, and the simplicity of California’s bigamy laws, California shows itself to be a very non-monogamous friendly state. The only liability that non-monogamists have is under the bigamy laws, and that’s only if there is actually multi-partner marriages within the family unit. Since this is only a concern for polyamorists and polyfidelitists, swingers and open relationships have no liability under California law.
Because of the limited liability that exists in California for non-monogamists, there really is only one way to avoid liability entirely for non-monogamists: Make sure you’re only married to one person at a time. As long as no one in the family possesses a legal marriage to more than one person at a time then there is no liability under California law.
California State Legislature. (2011a). (California Code 281). Sacramento, CA: California State Legislature.
California State Legislature. (2011b). (California Code 283). Sacramento, CA: California State Legislature.
California State Legislature. (2011c). (California Code 284). Sacramento, CA: California State Legislature.