I quit for a lot of people, mostly citing my kids during my early days. Still when I'm laying in bed at the end of the day thanking the good Lord for another day of sobriety, I'm not thinking of my wife, kids, coworkers, extended family, pets, or anyone else other than ME. Everyone else benefits from my sobriety and for that I'm extraordinarily thankful, but ultimately it's me who doesn't go to bed hating himself for drinking or dreading waking up hungover. I guess there's a hearty helping of selfishness there, but so what if it keeps me sober?
Another term that I struggled with before I became sober is "normal" drinkers. These folks that supposedly can have one or two, then happily move on with their lives for weeks in between. That's great, and I know such people exist; however, I think they're fewer and farther between than the beer and liquor companies would have us believe. Most people I considered "normal" drinkers before now strike me as on a slippery slope for serious problems, especially DUIs.
Quit for her Luthin if it gets you immediately sober, but trust me: In a few days or weeks your sobriety will become more and more a gift to yourself.