If you proven over and over that doing it on your own doesn't work...Try something different...I'd recommend AA/NA for you...At least try it...Sounds like you need some support from people that know how to do this...I know...I needed it too.
As far as telling your friends go...I told mine that my life depends on me staying sober and I can't be around you anymore...If they were good friends...They understood it...If they didn't understand it...Who cares...They weren't friends anyway.