what are the different types of relationships that exist?
['Close friendship — being close friends.', 'Courtship.', 'Long-term relationship (LT —R) Monogamy — having a single long-term sexual partner or marriage to one person. Polyamory — having multiple long-term sexual partners. ... ', 'Free union.', 'Engagement.', 'Marriage. Marriage partners. Husband. ... ', 'Civil union.']