Annulment is a legal procedure ending a marriage which is different from divorce as it puts the parties back in their original position, as if the marriage had never taken place. This can be a useful option if you don’t want to get divorced.
To get a decree of nullity your marriage must be void or voidable.
A marriage will be void if, for example, either person is already married; the parties to the marriage are of the same gender or where either person is under 16. If your marriage is void it is invalid from the beginning and can be treated as if it never took place. An application for annulment does not need to be made, although it is usually advisable to make an application for annulment.
Your marriage may be voidable for a number of reasons including where the marriage has not been consummated; if either party did not validly consent to the marriage (for example, if you were forced or pressured into marrying) or where either party is seeking gender recognition or has changed their gender. If your marriage is voidable it will be valid until it is annulled by a decree of nullity (an order from the court). Annulment is likely to be appropriate in cases of forced marriages.