Bigamy is a serious misdemeanor in Iowa. The only surprise is that it is a misdemeanor since sex is involved and most everything involving sex is a felony. Bigamy is one of those crimes having been on the books since time immemorial the purpose of which most assuredly was property. The probate courts would be in a mess if more than one wife or husband showed up upon the death of the spouse. By simply not recognizing the second marriage solves the problems associated with multiple spouses. Maybe the Mormons have the solution to these thorny property issues.
Considering the fact that half the population now cohabitates, we just don't worry about bigamy any longer. People don't marry, they merely live together. They do have fiancees however. A fiancee now indicates someone you are living with wherein there is a sexual relation. Fiancees may change regularly and often and many are what are termed serial fiancees. This is clearly demonstrated by the number of children a woman has by different men. She is a serial fiancee. Now the men are less easily identified in that they usually don't take their children with them when moving on to another fiancee. They too are serial fiancees. For these people bigamy is not an issue. Where bigamy may be an issue is in the wealthier portions of society where a person's main interest is property. In these situations, it has been known, that a person may serially marry for the purpose of acquiring wealth whether in the form of property, money, insurance proceeds, etc. Here probate may be a problem causing extended litigation. In the example of the serial fiancee previously mentioned, property is usually not an issue. No probate problems will arise, at least none the social workers can't iron out.
It is clear then, that the crime of bigamy is strictly for the benefit of probate referees and the courts and is reinforced by the 7th Commandment which strictly prohibits adultery. It would be interesting to know whether the concern over property or the religious injunction came first. My guess is that the concern of property came first and the religious injunction subsequently to give it effect. The issue of multiple spouses was compounded by the issue of multiple children by multiple spouses. What then? Just a real mess when it comes to dividing everything.
The English have always been perplexed by the problem of illegitimate children which naturally arises in cases of bigamy. Shakespeare is full of bastards; a term so passe now that not one in 50 school children have ever heard the word let alone know what it means; and luckily so, since half of them are in fact bastards.