An annulment can be granted in the Commonwealth of Virginia if the marriage is void, voidable, or obtained by fraud or duress.  These are a marriage obtained without a license or a marriage when either or both parties are under the age of sixteen and parental consent is not obtained and a party lacking the mental capacity to consent to a marriage.  It is also:
(1) A marriage entered into prior to the dissolution of an earlier marriage of one of the parties;
(2) A marriage between an ancestor and descendant, or between a brother and a sister, whether the relationship is by the half or the whole blood or by adoption;
(3) A marriage between an uncle and a niece or between an aunt and a nephew, whether the relationship is by the half or the whole blood.

 Examples of a marriage obtained by fraud is one party failing to reveal that he or she is or was a prostitute or failing to reveal any prior marriages or lying about the number of prior marriages.  A marriage under duress is one forced upon the other by fear or intimidation—think “shotgun wedding.”
 A marriage may not be annulled in it is proven that the party petitioning for the annulment has cohabitated with the other party after learning the facts that could allow an annulment or after the parties have been married two years.
 The Virginia Code that applies is:

§ 20-89.1. Suit to annul marriage.
    (a) When a marriage is alleged to be void or voidable for any of the causes mentioned in §§ 20-13, 20-38.1, 20-45.1 or by virtue of fraud or duress, either party may institute a suit for annulling the same; and upon proof of the nullity of the marriage, it shall be decreed void by a decree of annulment.
    (b) In the case of natural or incurable impotency of body existing at the time of entering into the marriage contract, or when, prior to the marriage, either party, without the knowledge of the other, had been convicted of a felony, or when, at the time of the marriage, the wife, without the knowledge of the husband, was with child by some person other than the husband, or where the husband, without knowledge of the wife, had fathered a child born to a woman other than the wife within ten months after the date of the solemnization of the marriage, or where, prior to the marriage, either party had been, without the knowledge of the other, a prostitute, a decree of annulment may be entered upon proof, on complaint of the party aggrieved.
    (c) No annulment for a marriage alleged to be void or voidable under subsection (b) of § 20-45.1, subsection (b) of this section or by virtue of fraud or duress shall be decreed if it appears that the party applying for such annulment has cohabited with the other after knowledge of the facts giving rise to what otherwise would have been grounds for annulment; and, in no event shall any such decree be entered if the parties had been married for a period of two years prior to the institution of such suit for annulment.
    (d) A party who, at the time of such marriage as is mentioned in § 20-48 or § 20-49, was capable of consenting with a party not so capable, shall not be permitted to institute a suit for the purpose of annulling such marriage.