Your partner is already addicted to a high level, it is very severe. You're as close to him could be a cure for addiction. I know you're upset with his habit, but you can not leave him. You should keep him busy with other activities. You must know his likes other than gambling. You must persuade him to perform another favorite. And make sure it is the most preferred favorite things besides gambling, so that he could possibly be interested. At least to reduce his addiction to gambling.