US citizen marriage to Egyptian

I am planning to marry an Egyptian man in the state of Washington. He is a student at the university here on a fellowship. Once we are married I plan to petition for a Green Card on his behalf so he would become a permanent resident in the US.
The complication is that he already has a wife in Egypt whom he is separated from; however, since he is a devout Muslim, terminating the marriage would be difficult, if not impossible. In addition, according to the laws and culture of his country, it is legal for a man to have more than one wife.
My question is: what are the possible legal ramifications of us marrying? Would he be considered married in the United States even though in Egypt he is allowed to marry more than one woman? Please let us know what we need to do to make this a legal marriage.
I appreciate your help!

You cannot marry legally in the US. It is bigamy and a crime.

He must divorce. Muslims can divorce. It is not rare at all.

I have this question i'm a US citizen and we want to get marry to Egyptian and want to know what are the steps I need to do...like is there a way like a fiancee visa ...can you please let me know what are the steps we need to take ...thank you