Habitual Drunkenness as Grounds
Habitual doesn't necessarily mean constantly. Your spouse need not be a diagnosed alcoholic; it is sufficient that his drinking has caused your marriage to break down. It must be a regular habit, enough so that it has interfered with your relationship and his ability to provide for the family.
Proving Your Grounds
You can't simply tell the court that your spouse is habitually drunk and expect the judge to grant you a divorce. You must prove your allegations -- and typically, the burden is twofold. You must establish that he drank to excess, and then you must prove that the habit harmed your marriage. This can be a significant challenge, because most states allow your spouse to raise legal defenses against your allegations. He can tell the court that you forgave him -- and if he never became intoxicated again after this point -- the grounds for divorce are invalidated. He can allege that you did something wrong, as well, such as an affair that caused him to begin drinking. He can allege that you encouraged him to imbibe. If he can prove any of these things, you don't have grounds. However, a no-fault divorce would still be an option.