He can "marry" as many as he wants. That is not a crime.
Tory, 50 states have statutes against bigamy. In most of them it is a felony.
Multiple girl friends you can generally get away with, multiple licensed marriages are another game altogether.
Wrong, wrong, wrong. You can have as many ersatz marriage ceremonies as you like. However, if your second, third, etc. "wife" is unaware or you existing marriage(s), she is termed a "putative" spouse (those in the male cohort of the Guild enjoy misstating the word as "punitive" spouse), and has certain property rights in civil law.