These days, so called Christians spoiled the healthy marriage practices of Christianity by following the worldly ways of unbelievers. They also call themselves modern Christians. They choose their life-partners by themselves. In some countries man and woman live as husband and wife even before marriage and choose to live with a man or a woman who gives the partner the maximum pleasure. They marry eventually, but, after a while, begin to dislike each other.
Pentecost people conduct marriages of such people.
Later the persons united in such marriages separate from each other and choose to live with somebody else. Yet a few practice polygamy. Those are all fornicators who have deviated from the path set forth by God. At the beginning God created Adam. But Adam did not roam about in search of a partner.