A marriage is more stable when compatibility is established due to shared cultural background and values.

In a tribal context, we Europeans, though not engaging in close-cousin marriages, would have been living in tight-knit clan groups whereby clan members would interact with members of the other allied clans at tribe gatherings and other occasions.

It would have been like a “small town” type of environment where if everyone doesn’t know everyone, you can place people by asking who their kin are.

– Tribalism & Kindred by CE

For myself, I accept the view that the peoples of Germany have never contaminated themselves by intermarriage with foreigners but remain of pure blood, distinct and unlike any other nation.

Their marriage code, however, is strict, and no feature of their morality deserves higher praise. They are almost unique among barbarians in being content with one wife apiece – all of them, that is, except a very few who take more than one wife not to satisfy their desires but because their exalted rank brings them many pressing offers of matrimonial alliances. The dowry is brought by husband to wife, not by wife to husband. Parents and kinsmen attend and approve the gifts – not gifts chosen to please a woman’s fancy or gaily deck a young bride, but oxen, a horse with its bridle, or a shield, spear, and sword. In consideration of such gifts a man gets his wife, and she in her turn brings a present of arms to her husband. This interchange of gifts typifies for them the most sacred bond of union, sanctified by mystic rites under the favour of the presiding deities of wedlock. The woman must not think that she is excluded from aspirations to manly virtues or exempt from the hazards of warfare. That is why she is reminded, in the very ceremonies which bless her marriage at its outset, that she enters her husband’s home to be the partner of his toils and perils, that both in peace and in war she is to share his sufferings and adventures. That is the meaning of the team of oxen, the horse ready for its rider, and the gift of arms. On these terms she must live her life and bear her children. She is receiving something that she must hand over intact and undepreciated to her children, something for her sons’ wives to receive in their turn and pass on to her grandchildren.

By such means is the virtue of their women protected, and they live uncorrupted by the temptations of public shows or the excitements of banquets. Clandestine love letters are unknown to men and women alike. Adultery is extremely rare, considering the size of the population. A guilty wife is summarily punished by her husband. He cuts off her hair, strips her naked, and in the presence of kinsmen turns her out of his house and flogs her all through the village. They have in tact no mercy on a wife who prostitutes her chastity. Neither beauty, youth, nor wealth can find her another husband. No one in Germany finds vice amusing, or calls it ‘up-to-date’ to seduce and be seduced. Even better is the practice of those states in which only virgins may marry, so that a woman who has once been a bride has finished with all such hopes and aspirations. She takes one husband, just as she has one body and one life. Her thoughts must not stray beyond him or her desires survive him. And even that husband she must love not for himself, but as an embodiment of the married state. To restrict the number of children, or to kill any of those born after the heir, is considered wicked. Good morality is more effective in Germany than good laws are elsewhere.

Germania by Cornelius Tacitus

Think we could learn a thing or two from these Germanic barbarians? They were practicing The Old Ways.