You cannot be outside of the US for more than 6 months as a legal permanent resident (LPR). The conditional part of your LPR status is fulfilled if you have lots of bills, bank statements, contracts and other mutual assets / liabilities together. If you do not have that, then your case will be denied. Your husband should find an immigration lawyer to help defend the case as soon as possible.
Hire an immigration attorney in the US immediately.You are likely entitled to be admitted to the United States as a returning resident as the law provides that you are entitled to have your case denial reviewed by an immigration judge in removal proceedings.
Without knowing why it was denied, it is difficult-to-impossible for us to comment on your appeal rights.
Have your husband meet with an immigration lawyer to review all the papers that were send in.
PROFESSOR OF IMMIGRATION LAW for over 10 years -- This blog posting is offered for informational purposes only. It does not constitute an attorney-client relationship. Also, keep in mind that this is an INTERNET BLOG. You should not rely on anything you read here to make decisions which impact on your life. Meet with an attorney, via Skype, or in person, to obtain competent personal and professional guidance.