Grounds for an annulment in most states is that one spouse refuses or has an inability to consummate the marriage. Basically, this means that one spouse refuses to have sex with the other spouse. Since that is your situation, contact a lawyer to start the process. Doing so quickly, within just a few weeks of marriage, is your best approach. Do not wait to protect your rights.
You might find my Legal Guide helpful "How to Choose A Lawyer For You"
You might find my Legal Guide helpful " What Do I Tell My Lawyer"
Good luck to you.
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Below is a link to the California Court's Self-Help Center. It looks like a great site to get forms and to learn about the specific process. One interesting thing about it is that you actually have to prove grounds for an annulment, you can't just say "irreconcilable differences." With a divorce you don't have to prove anything. A divorce may be easier for you, especially if you have to do it yourself.
I have also linked for you the LA County Courts website for family law self-help. Note that an annulment is actually called "nullity of marriage."
I hope all goes well for you.
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