You have a difficult argument to make. Contact a contract/business attorney. The only significance of your being a domestic partner is to fulfill the special relationship requirement in arguing unjust enrichment.
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The Statute of Frauds requires a contract for more than $500 to be in writing. Yo may be able to argue that it is "unjust enrichment" if you went into the venture with "clean hands" which is in question since you tried to hide your conviction by putting it in her name.
Check out this link to New York Partnership Law. It will give you an idea about how partnership is proven:
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An oral contract is just as binding as a written contract, but this certainly doesn't end the matter. Legally the contract may be binding but an oral agreement with no witness and no voice recording can end up being problematic in terms of evidence. But again that is a question of evidence and not of law. Once of the attorneys who responded stated that you lack clean hands because you hid your ownership of the business. I'm not sure why that would indicate that you have unclean hands. There's not enough information here really to do a complete analysis. You say you worked for free. Did you agree to work for free or was this sweat equity that by agreement was supposed to translate into an equity share?
This answer is merely an answer to a general legal question and does not constitute any attempt to set up an attorney/ client relationship. I do not advise you to act solely on the basis of this or any other answer to a general legal question because every legal situation is unique and must be studied uniquely.