If your marriage is not valid for any reason then you can have the marriage "Annulled". This is done by presenting a "Nullity Petition".
Examples of when you may seek an annulment of your marriage is where:
1. At the time of the marriage your partner was already married to someone else
2. It has not been consummated
3. One of you was under 16 years of age when you got married.
4. You have inter-married (i.e. married a close relative).
5. Your partner had venereal disease at the time of the marriage and they were aware of this at the time, but you were not.
You must apply to annul the marriage within a reasonable period of time, in some cases this will be within 3 years. There is no requirement to have been married for 12 months before applying for a nullity.