Dear Sir/ Madam,
I would like to find out some information regarding the stay in usa more than 90 days. i am a british passport holder and i am visiting USA on visa weaver programme and now i have met somebody who is US citizen therefore would appreciate stay in USA more than 90 days to get to know him better as it would save me all the hassell of going back and forth to UK.
your time is much appreciated.
Start at this site (US State Department Passport office)
Since I was married to a Brazilian citizen for 7 years who came and lived here while we were married (and received a green card), I would like to advise you further, but the laws have changed so much over the past few years (since 2011) that I really have no idea what they are from year to year anymore. If you have very specific questions, the best place to get answers would be at a US embassy in the UK.
The list of all US embassies is located here: