This comment might not be popular on a quick knee-jerk level, but it's worth getting out there for accuracy.

Under "Many partners" you've got Singlehood, Friendship 'with benefits', Polyamory.

You're missing one of the most common historical kinds of relationships - monogamous commitment from woman to man, man taking care of multiple households in a committed way.

The first Tokugawa Shogun, for instance -

http://en.wikipedia.org/wiki/Tokugawa_Ieyasu#Ieyasu_as_a_person

16 children with 11 wives and concubines.

King Ts'ao Ts'ao of Wei -

http://en.wikipedia.org/wiki/Cao_Cao#Family

Muhammad -

http://en.wikipedia.org/wiki/Muhammad#Wives_and_children

It's not a Western tradition. The West has a strong romantic/platonic love ideal, that moves into monogamy under Christianity, and some non-monogamy later built on some mix of liberalism, enlightenment values, and humanism.

But still, it's been a very common family/dating/relationship through history. It still persists, though it doesn't get much media coverage.

Current Sheik of Dubai -

http://en.wikipedia.org/wiki/Mohammed_bin_Rashid_Al_Maktoum#Personal_life_and_education

Current Prime Minister of Italy -

http://en.wikipedia.org/wiki/Silvio_Berlusconi#Sexual_scandals