If divorce revokes the conditional green card, and all sponsorship is automatically withdrawn including the I-864, does that mean I am no longer responsible for the alien national. What about the 10 year responsibility. What if he manages to get conditions removed with the help of an attorney and is successful in his waiver application. There is no joint property, no children and no joint names in anything. He cannot claim extreme hardship, being from Canada and there's no abuse of any kind in our relationship. One attorney told him his chances are very slim, while another attorney said he will work out something. Thank you.

Divorce revokes the conditional green card... correct BUT sponsorship is NOT automatically withdrawn unless you report to USCIS to withdraw the sponsorship. So if you fail to report this issue, you will be responsible in case he takes welfare. The term is 10 years... unless your spouse permanently leaves US or naturalized.

From your info given, it's hard to claim extreme hardship, even in abuse cases, approval rate is less than 70%. If he gets screwed by some attorney, it's his business, not yours. Nothing you can do at this point... just file a divorce and move on with your life. File restraining order if he might be harm to you.