Concealment of a DUI is not grounds for annulment. Fraud as a ground for the annulment of marriage must constitute concealment of something that is vital to the relationship and the essence of marriage. Neither are drinking problems nor change in character grounds for annulment. If you really want to terminate your marriage, then maybe the more feasible course is to file for divorce. Consult with a divorce lawyer to find out if you have enough grounds to file for annulment or if divorce is really the best course.