I tried to give up drinking for a month towards the begining of the year. I wasn't an alcoholic (not even close) but I was drinking around 4/5 night a week. The problem was not the regualrity of my drinking but the amount I would put away, I would run a very fine line between beng a funny sociable drunk, to being a complete nightmare. People started distancing themselves from me on nights out, and then it got to the stage where I would not be invited at all.
I managed to obstain for about a week, which to be honest, left me quite dissapointed in myself. But it did really wake me up into realising that I needed to exhibit some self control whilst I was out. Since then I have been much, much better. I know what I cant drink and if that's the only option I don't.
I think it all obviously comes down to will power, and will power alone. And to be honest I think you have done fucking well to stay off the sauce for five years, that's something I could never do.
Good luck for the future.