Well, in my opinion, the first thing that needs to be addressed is that she was lying to both of you. She told the husband it stopped, and told you that he still gave her consent for the two months? Correct?
if that is true, then you need to decide if a) you are okay with being lied to about something like consent and B) if you are willing (like Denuseri said) to continue this relationship with her behind the husbands back and without his consent. Like i said, just my opinion. but morals and trust would play a big part in this for me.