Marriage is not simply a private contract between two individuals but also has to be registered with the state and meet certain requirements. If these requirements are not met, the state may find that no real marriage ever existed. This may be a problem for the woman in particular, since she has no claim to any property gained during the alleged marriage (in a community property state) or any type of alimony after a divorce. This is especially true if the state does not recognize common law marriage.
I found two cases involving Muslims that illustrate these problems. The first is In re Marriage of Vyronis, 202 Cal. App. 3d 712 (1988). This case involved a type of marriage permitted by Shi'ite Muslims called mut'a or temporary marriage. Mut'a is not permitted by Sunni Muslims, who make up about 85% of all Muslims. Temporary Marriage in Islamic Law is a Shi'ite article explaining the rules of mut'a.
In Vyronis, Speros Vyronis (a non-practicing Greek Orthodox Christian) and Fereshteh, an Iranian Muslim, made a mut'a marriage. Fereshteh was not familiar with American law and thought that the marriage would be recognized as valid since Vyronis told her it was. It was only when she filed for divorce that she discovered the truth. She then attempted to claim status as a "putative spouse" on the grounds that she had a good faith belief that she and Vyronis really had been married. This was the issue before the Court of Appeals of California. The court looked at the circumstances of the marriage and found it that it would be "unreasonable" for Fereshteh to think that her mut'a marriage was a valid California marriage:
In sum, the alleged private marriage went unsolemnized, unlicensed and unrecorded. Thereafter, the parties did not cohabit, or hold themselves out as husband and wife, and in no way approximated the conduct of a married couple. Because the facts were at odds with the formation and existence of a valid marriage pursuant to California law, Fereshteh could not rely on Speros's statements reasonably to believe she was married. Notwithstanding Fereshteh's sincerity, her belief was unreasonable and therefore not in good faith.
Vyronis, supra at 722.
It's interesting to read some of the factors the court considered. For instance, they noted that Fereshteh "did not use Speros's surname". I guess this was a still a significant factor even in 1988 California! Feminists might be surprised by this one.
Actually, Muslim women in many cultures do not take their husbands' surnames and some Muslims actively believe that they should not do so because the Quran says that children should be named after their fathers (Quran 33:5; however in context the verse seems to mean not to name adopted children after their adoptive families but they should keep their original names).
Another factor cited by the court is that "the parties did not commingle their finances". In an Islamic marriage, the property that the wife brings to the marriage is kept separate so that it is under her exlusive control. The husband supports the family entirely out of his own finances (if the husband fails to provide, the wife can take the money without his permission, according to a ruling of the Prophet Muhammad, peace be upon him). Thus the husband and wife keep separate finances.
A third point that the court mentioned is "nor did they assume any support obligations for one another". This is one of the unique characteristics of mut'a marriage and one of the reasons that Sunni Muslims don't permit it. Mut'a does feature a mahr, but the husband does not provide any support during the marriage and the husband and wife do not have any inheritance rights on each other as in a normal marriage (a widowed spouse is always entitled to some fraction of the deceased's estate under Islamic inheritance law). Mut'a is called "temporary marriage" because the marriage is made for some fixed period of time. The marriage ends automatically at the end of that time unless the contract is renewed so there is no divorce (it's not clear from the court's opinion what the term on the mut'a was here or if this factor was considered) and therefore the wife does not get any divorce provision either.
Given that Sunni Muslims don't recognize mut'a as a valid marriage, maybe it's not suprising that the California Court of Appeals didn't either. I tend to think that the courts should recognize any private contract between two people and enforce the terms of that contract; but Fereshteh wasn't due any money from Speros under the mut'a contract anyway.
This is definitely an unusual case.
The second case that I found was Farah v. Farah, 16 Va. App. 329 (1993). Here, the couple were married in England through a proxy ceremony. This type of marriage is valid under Pakistani law. It doesn't meet the requirements of English marriage law; I don't know if an English court would recognize it under comity as it recognizes marriages performed in Pakistan under Pakistani law.
The Court of Appeals of Virginia refused to recognize the marriage because it said that the marriage has to be valid under the laws of the country where it is celebrated. Since the marriage was celebrated in England, the court looked to see if the proxy marriage was valid under English law and it wasn't.
The lesson from Vyronis and Farah seems to be not to make private marriage contracts. Like I said, I think this is unfortunate. Any other contract that a man and a woman make would be upheld, so why not a contract of marriage?