From the link below, it seems that DN's 5 year work Visa made it imperative that he eventualy get married so he can stay here:
Poker Royalty
"Possibly the most impressive negotiation was Balsbaugh's ability to broker an agreement between Negreanu and the US Government.
Negreanu, who is a Canada native, was subject to immigration laws that restricted how long he could reside in the United States. Balsbaugh contacted a prestigious immigration lawyer in Dallas, Texas to work on the case.
Before long Negreanu was granted a five-year workers' visa which was previously reserved for high-end entertainers and professional athletes."