Yes, divorce does not terminate your obligations under the Affidavit of Support. She became a permanent resident the moment she entered the US and you cannot take back the Affidavit of Support. Petitioning somebody for immigration is a serious commitment and you should not have signed the Affidavit of Support if you didn't want to take the risk that marriages don't always work out.
She can do Removal of Conditions (I-751) on her own after divorce. Your best hope is that she becomes a US citizen as soon as possible, as that will terminate your obligations under the Affidavit of Support.
Also, note that even if you do not fulfill your obligations under the Affidavit of Support (to provide her with enough income to meet the poverty level if she herself doesn't meet that level), it will most likely still not affect you. The only ways in which it can affect you are: 1) if she sues you (which is unlikely because it is expensive to sue in federal court), or 2) if she uses a need-based government benefit and the state government sues you for the costs (which is also unlikely because pretty much no states are doing this or considering doing this, due to the costs, etc).