The sole ground for divorce in Colorado is irretrievable breakdown of the marriage.

Annulment

In a divorce, the court declares the marriage contract broken; in an annulment, the court says that there never was a marriage. Annulment is much more difficult to prove -- and is much rarer -- than divorce. If you want to go this route, you will definitely need to speak to an attorney. Of course, if you want an annulment for religious reasons, you'll need to consult with your priest, minister, or rabbi as well. (Read)