My wife and I have been married 10 years. She is canadian and has her green card. I am american and we live in the US. We have 3 children born in the us and are citizens. If we divorce, does she have to leave the US?

No, if she is a LPR (lawful permanent resident with 10 years greencard), divorce has nothing to do with her status.

Good to know. Actually, married 10 years, 10 years in the system, green card for 6.5 years (INS was slow). It expires in 2012. What then? Does she need me for paperwork or can she do it on her own? It's obviously not a sham marriage. Shambles is another story, but at least not fraudulent. Thanks for your help.

She can be on her own.. no need of your support on documentation.