In fact, attempts to introduce free love in family relations date back to the sixties hippie fashionable youth movement, but the overall style of life unlike other young nihilists had no proof of success. And now barely open relationship in a particular pair could be the phenomenon of mass character. Although it does deny the existence of such pairs would be unreasonable. But the question is not about whether there are such pairs, and how their relationship viable.
Although the human soul at all times and was considered a mystery, the emergence of jealousy is not so mysterious phenomenon. And it would be naive to think that an open relationship sooner or later will not cause its natural attacks at least one of the spouses. And since, as stated in the statistics, the initiators of such relationships tend to favor men, whereas women sometimes you just have to make sacrifices in order to save the marriage, it is the female jealousy and capable of rushing hurricane sweep once glowing affection.
In addition, at any circumstances was, really happy married couple would never dare to similar experiments, for even a hint of them would mean the possibility of intra-family problems. But even if one or more precedents free love were hardly relations will remain the same, not to mention their hardening.
And looking at the hundreds of generations of our ancestors who lived by the canons of morality, as well as on the current youth and cynicism prevails everywhere, comparing times and values of life, still could not be called an open relationship in marriage promising and suitable for two intelligent and loving people. In any case, because love - is not only the desire and attraction to each other, and a sublime feeling.