Kedusha, you wrote:
if you are sincere, and take real steps to fight this (one day at a time, and always with the help of Hashem), then, as far as Hashem is concerned, you've been sober for 1000 years.
Kedusha, thanks for pointing to this important yesod. Even a sincere THOUGHT of teshuva can cause a Yid to leap to from the lowest to the highest level.
See Rambam, Hilchos Ishus Perek 8, h. 5, where he writes: " (When a man tells a woman: "Behold, you are consecrated to me) on condition that I am a Tzadik", even if the person is known to be a rasha gamur, there is doubt (regarding the status of the kiddushin and) the woman is considered consecrated. For it is possicle that he had thoughts of teshuva in his heart at that time".
Note that the mefarshim explain that the doubt only exists because we can not be aware what is hapening within the person's mind. If we could be sure he had sincerely repented, he is considered a tzaddik regardless his previuous conduct. This demonstrates the power of teshuva, how one sincere thought can transform one spiritual level from one extreme to the other. (taken from the Mishne Torah, Feldheim edition).