Deity-worshipers, animists and theists alike, have a lot in common with people who enter into relationships because of item 4. below. Often there exists among them a fear of death, which creates a fear of suffering, which creates a fear of ( loneliness, public shaming, poverty, sickness, etc. ). I think of them as the same sort of needy children, who never acquired independence.
--
It seems, most people marry out of one of the following :
1. social convention ( less personal preference )
2. regulatory mandate ( formal, or informal rules, with penalties for non-compliance )
3. capitalism ( access to goods, services, currency, class markers )
4. fear of abandonment ( needing someone/s to standby and pick them up when they fall )