You don't always have to go through divorce proceedings to end a marriage. In some cases, you can request a marriage annulment, which legally ends the marriage and declares that it was never valid. Annulment rules vary by state, so make sure you check your state's laws before you start annulment proceedings to know where you stand. Some states also apply annulment laws to domestic partnerships.

If you want to legally end a marriage, you have two options: annulment (called nullity in some states) and divorce. An annulment cancels a marriage, declaring that the marriage was never valid. Effectively, it erases the marriage completely, as if it never existed in the first place.

A divorce, referred to in some states as a legal dissolution, is quite different. This ends a valid marriage, restoring both parties’ single status and allowing them to legally marry again. In most cases, a divorce is more complicated than an annulment, particularly if there are marital assets to be divided, debts to be settled and custody, visitation and support of children to determine.

Either spouse can start annulment proceedings and must prove that they have the grounds to do so. Annulment rules vary by state but in general, the following are grounds for annulment:

• Bigamy: Either party was already married to someone else at the time the marriage took place.
  
• Forced consent: One spouse was forced or threatened into the marriage.
  
• Fraud: One spouse agreed to marry based on the lies or misrepresentation of the other spouse.
  
• Marriage is prohibited by law: The parties have a familial relationship that makes their marriage incestuous.
  
• Mental illness: Either spouse was mentally ill at the time of the marriage.
  
• Mental incapacity: Either spouse was unable to make informed consent to the marriage due to being under the influence of alcohol or drugs at the time.
  
• Inability to consummate marriage: Either spouse was physically unable to have sexual relations.
  
• Underage marriage: Either spouse was too young, according to state law, to enter into marriage without parental consent or prior court approval.

A marriage may be annulled if it is void or voidable – these are not the same thing. A void marriage is one that didn't legally exist in the first place and is against the law in most states, such as incestuous marriages (where the parties are closely related by blood) and bigamous or polygamous marriages (where one spouse was married to someone else at the time of the marriage). On the other hand, a voidable marriage, i.e., one you were tricked or forced into, is considered a legal marriage, but may still be annulled if you can satisfy your state's requirements.

You can file for annulment only within a certain time after getting married. You can usually annul a void marriage as long as both you and your spouse are living, because in the eyes of the law, it was never valid at all. For a voidable marriage, the annulment time limit varies by state and can range from a few months to several years, with the time frame usually beginning from the date you became aware of the circumstance that makes your marriage voidable.

For example, in Colorado, you have six months if your spouse tricked or forced you into the marriage, and one year if your spouse is impotent. In Ohio, you have two years to file for annulment of a voidable marriage. In California, you have four years for most grounds, and on the ground of unsound mind, you can request an annulment at any time before the death of either party.

If you want to annul your marriage on the ground that you or your spouse were underage at the time of the marriage and did not have parental consent or court permission to marry, some states apply different time frames. The age of the parties at the time the annulment is requested is often a factor.

For example, Colorado has a two-year limit for annulling a marriage on this ground, while other states remove the right to an annulment after parties reach the age of majority. In California, you can annul an underage marriage up to four years after reaching the age of 18, although your parents can file for an annulment on your behalf before you turn 18.

You can file for an annulment at the district court in the county in which you or your spouse live or got married. Check your state's specific requirements. For example, in Colorado, you can start your case immediately if you got married in that state. If you didn't marry in Colorado, either you or your spouse must have lived in Colorado for at least 30 days before starting your case. In California, you can file for annulment there as long as you live there at the time, with no required length of time for residency.

You can request an annulment on your own, or you and your spouse can file together (as petitioner and co-petitioner). Either way, you must be able to prove that the marriage was not valid.

The clerk's office will provide instructions on how to file for an annulment and give you the correct forms (the same forms you would use to file for divorce or legal separation), which must be completed in full, signed and handed to the clerk's office. You must clearly explain on your forms your legal reason for asking for an annulment.

A filing fee is payable, which varies by state. In Colorado, the filing fee (as of February 2020) is $230. In California, the filing fee is $435. If you cannot afford the fee, you can request a fee waiver by completing a fee waiver form, which is also available from the clerk's office.

If you are not making a joint request for an annulment with your spouse, you are the petitioner and she is the respondent. This means she must be served with the forms and then has the opportunity to file a response (typically within 30 days, but this also varies by state).

In the response, she can either consent to the annulment or oppose it. If she opposes it, she must provide clear reasons why. The response is filed with the court and served on the petitioner, and a judge will then review all paperwork and decide what the next step should be.

You may receive a case management order, a document containing information about your case such as the date of an initial status conference and requirements for filling out additional forms, such as a sworn financial statement, a separation agreement and a parenting plan. The exact process and requirements depend on the circumstances of each case.

All annulments require a court hearing, in which both parties have the chance to present their case in front of a judge. You do not need to be represented by a lawyer in court, but you may want to consider seeking legal representation, particularly if your case involves other issues, such as property division or custody and visitation of any children of the marriage.

If the court denies your request for an annulment, you can file an amended petition changing your request from an annulment to a divorce or legal separation. You must follow the instructions and ensure you meet the residency requirements of your state.