I think it goes beyond the issue of romantic flights and enters the area of separation between subjective phenomena, such as religion, spirituality, emotions etc. and the state - which causes a lot of confusion at every imaginable level.
At one level the confusion is between feelings of love and intimacy and a social institution of marriage. People fall in love and want to express or confirm their emotions by entering into what is essentially a business contract. This is as someone was yearning for a warm home atmosphere and in response to a develop ad, entered a contract to buy a piece of real property to satisfy those yearnings.
The danger of that situation is that the subjective feelings may burn out or perhaps fail to be realized by the contract the person entered - but the contract remains valid and binding regardless that person's feelings. That can lead to a lot of frustration.
That situation can be avoided if (1) there many alternative ways of expressing one's subjective feelings, e.g. various forms of socially accepted informal unions, so people have various means of "confirming and expressing" their mutual feelings that do not entail entering a legally binding contract. If they choose to enter such a contract, however, they can be clearly informed by a disclosure statement (akin to that on the back of a credit card application) outlining the basic consequences of their agreement, such is financial and legal responsibilities, as well as other restrictions (e.g. exclusive rights to sexual gratification, if that option is selected), and explicitly informing that entering such a contract is not tantamount to "marriage" or any other subjectively defined form of interpersonal relationship.
That solution would also solve the confusion regarding homosexual marriages, group marriages, etc., which again stems from mixing subjective interpretations with legal contracts. Anyone could enter a legally sanctioned civil union contract - including two or more people of same or different sex - but in order to be "married" as defined by this or that religious tradition, they would need to file a separate application to a religious or cultural institution that hold the copy rights to bestowing that particular title.
That would eliminate a lot of nonsensical and pointless cultural wars that now pollute public debates in this country.
Wojtek