This person needs to be divorced first then he can get married to you. Otherwise the marriage will not be a valid and therefore you will not be able to petition for this person. Also if you try to marry him, he might be faced with bigamy (which is a crime in most states).
You can read more about marriage on the link below, check under publications.
Founder and Managing Attorney of Shah Peerally Law Group PC
Law Firm Deals in Immigration law, Bankruptcy & Debt Relief
Note: The above answer is provided for informational use only. One should not act or refrain to act solely based on the information provided. No attorney client relationship is created unless a retainer is signed by the attorney and the client.
My colleague is right - he must finalize his divorce first before entering into marriage again. Please speak with an experienced family law attorney to obtain information about how to file for his divorce from the U.S.
Renata Calderaro, Esq.
The Calderaro Law Group
12550 Biscayne Boulevard
Miami, Florida 33181
Follow us on Twitter: RenataCalderaro
On LinkedIn: http://www.linkedin.com/pub/renata-calderaro/3/959/536