Wisconsin is a no-fault state, so you can only file for divorce on the ground that your marriage is irretrievably broken. If you and your spouse file a joint petition stating this, the court doesn’t have to rule that a ground for divorce exists. Otherwise, you can file your own petition after you and your spouse have lived separately for a year. You don’t have to prove that any fault exists; your belief that the marriage is over is usually sufficient for the judge. Your spouse can argue against your ground only by stating that you haven’t lived apart for the required time.
Annulment grounds are far trickier than divorce grounds in Wisconsin. You must convince a judge that your marriage was illegal in some way from the start. For example, if teenagers younger than 16 somehow manage to marry without the permission of either their parents or the court, this union is annullable. If you or your spouse were not capable of understanding what you were doing when you married, if you were tricked or threatened into getting married, or if you got married only to find out that your spouse was physically disabled to an extent that prevents a normal married life, you can get an annulment and have your marriage “erased."
Children and Financial Issues
Factors of property and children are treated the same in Wisconsin whether you’ve filed for annulment or divorce. An annulment doesn’t make your children illegitimate; they still have the same right to financial support and a relationship with both parents as they would have had if you divorced instead. If you file for annulment, the first hearing addresses whether a ground for annulment exists, then you must proceed to a second hearing to deal with auxiliary issues such as custody and property. If you have children, both annulment and divorce require a parenting plan before a judge will grant you a decree. If you can’t reach one by consent, the court can appoint a guardian ad litem, an attorney to represent the interests of your children, while you litigate custody. A judge can also order a custody evaluation.
Wisconsin imposes a four-month waiting period between the time you file a petition for divorce and the granting of a divorce. There’s no waiting period for an annulment. If you have a clear-cut case that your marriage was not viable in the first place, you may be able to get an annulment more quickly than a divorce, especially if you have no children and haven't acquired property together. In this case, a second hearing might not be necessary.