Hahaha. Really? Ohhh dear.. she told you to catch a cab and go home? Goddd you could have a good one here

wow.. that was a shit test.. you should've ignored it and told her you wanted to stay a bit longer and pick up a few other women.. you told her your seeing different women so she decided to test you to see if what you was sayin is genuine.
You answered the question ok I guess.. I mean you could've told her your dating a few girls SPAM but your looking for that one right girl if you wanted an exclusive relationship
you wanted a fuck buddy you could've just said "I like to keep my options open" and then changed the subject.
Your state needs to be clear in order for your body to convey the correct signals, i.e. you want a fuck buddy? treat her like a fuck buddy and have it in the back of your mind she IS your fuck buddy.
As for the last bit of your question... only you can decide.. in order to help you, you should sit down and decide 5 must have qualites for a exclusive relationship, and 5 qualites for a FB that way when a girl meets either qualites you can decide from there