I agree with everyone, abs wouldn't have stopped this.
When you ride with your wife, or anyone else that has less experience and abilities than you do, SLOW DOWN! She admits that she saw you take the turn and thought she could too. That should tell you everything right there.
Maybe even let her take the lead so she can ride at her own pace and not try and keep up with yours. Just remember, stay back so she doesn't feel she's slowing you down.