Can my wife legally keep my kids from seeing me if I don't give up drinking?

My wife gave me an choice tonight. Quit drinking or she's leaving me and she'll never let my kids see me again. It was an easy decision...I won't quit drinking for her or them but will a court even give her that option? How will they know if I've been drinking? They can't force me to any kind of tests can they? I have a 24 year relationship with scotch that goes much deeper and longer than my time with her or my kids (neither of them are even 10 yet!). In my life (and I told her this when we got married) getting drunk is first in my life, my kids are second and she's third. Since she knew this going in would any court grant her full custody?