The Romantic image of the author as an alcoholic, drug addicted wild man makes for great biography but doesn't tally with the facts. Poe, Hemmingway, Dylan Thomas, and Faulkner saw serious fall-offs in creative output as they sank into alcoholism. The real biggies - Shakespeare, Balzac, Dickens - led sober, industrious lives.
The reason for this is obvious. Writing is brainwork that requires focus and energy. Even before drinking starts to impair the brain, it saps the vigor needed for sustained creative effort.
The same can be said for torrid affairs and drug use.
I do drink, and probably more than I should, but my life for the most part is orderly and sober. I go to bed around nine and get up at five. I do a little writing work each day before going to my regular job, where I am conscientious and generally well respected. I come home each evening to my wife, read, watch tv, eat a balanced meal, walk the dog and sleep. This is my life and a happy life it is. Happy, that is, from the inside. Viewed from the outside, it would be tedium itself: nothing more uninteresting than someone else's order and contentment.
My goal is to someday be so famous, a biographer will decide to do my life story, but then, on examining the facts of my life - good health, good marriage, good habits - will throw up his hands in despair and exclaim, "Why bother!"