Do what you need to do.

If you need to divorce, then do it. Donot worry about her status, unless she begs u. Every yeart there is a limit on number of green cards approved. You do your ex-wife a favor, means you do a bad thing to another person, who cannot get the green card in that year becuase your wife gets it. You should not be selfish, just considering your ex-wife. You need to consider what to do for the society for other people. I just do not understand y there is such selfish people here, just considering about themselives or their friends. You are may waste a chance which belongs to another person who is more appropriate to get the green card. Take my words: stop thinking about yourself, and your exwife, think about what to do to benift the whole world.