AnnaOnTheMoon, that is very helpful. I could easily have my mom and boyfriend write letters like that for me. You didn't apply ahead of time for a visa then? I probably will, because I don't want to be turned away at immigration, but that's comforting to know. How long was that visit?
I arrived on 17th October. Originally, I was leaving on 22 December, but I was invited to stay for the holidays, so will be going home somtime in January.
But, I've been a visitor this whole time, even though I've been staying with my boyfriend - I've gone out weekly to do touristy things, and on weekends have gone places farther away from his house because I am here as a visitor.
Like everyone else said, you can't just use the waiver to try to live with your boyfriend. I've got loads of documentation (train ticket stubs, attraction stubs, photos) to prove I've been visiting the UK just in case I need to at some point.
I only WISH it was that easy to just live with him, or I'd just not go home, but unfortunately, there are procedures to follow. Also remember that if you are there for 6 months as a visitor, then go home to apply for the 6 month fiancee visa you will have spent an entire year not working - and in order to get the fiancee visa, you have to prove funds just like for the visa waiver....so basically, if you aren't made of money don't visit for 6 months.
I know it sucks how US/UK couples sort of get pushed to marriage if they want to be together, and I wish there was an easier way to do it. But listen to people like Vicky and garry (and the other knowledgeable folks around here, like kitsonuk). They really know what they are talking about.
Since this is a sort of relevant question to the experts - if you stay 6 months on a visa waiver, can you get a visitor visa to return again before the year is up?