EEA Family Permit (Unmarried)
People who are able to demonstrate they have been living in a relationship akin to with an EU citizen for the most recent two years may be eligible to apply for an EEA Family Permit on this basis. Dependent children can also be included on any such applications. If you are not yet , you should apply for entry through the British authorities in your home country before the UK.
EEA Family Permit (Married)
En este link van a encontrar informacion muy interesante http://www.ukresident.com/content/articles/uk-immigration/european-track/general-guidance-on-the-eea-rules-r117
Sobre fiances, spouses, de EEA nationals,que pasa si se separan etc etc