Visa for non-EU family of EU national (London)

Hi guys

I'm looking for a visa genius or someone who has been through this process and who would be able to advise me...

I have sifted through the vast amount of info on the UK Home Office site and still cannot find a conclusive route to applying for a visa.

My fiance is a Dutch national and I am South African. He is being relocated to London for work so I will be joining him.

Do I apply as a non-EU family member of an EEA national?

Do we have tp be married first or just able to show we are in a "durable relationship" - some parts of the home office sight specify a "wife" but others specify a "durable relationship"

Can I work on this type of visa?

Is the visa valid for 5 years? After this do I apply for naturalisation? (So many different things mentioned, indefinite leave to remain, permanent residence etc etc - are these all different?)

If I was on this type of visa would I be ble to travel into the Schengen area without applying for an additional visa?

Thanks for the help!!!

Bianca