I hope it wasn't your attorney that made that recommendation. New Jersey is a "one party consent" state, meaning it becomes a criminal act to record a conversation with another party unless that other party gives his/her consent. New York is also a one party consent state. This means that you MUST get her consent if you wish to record a conversation that she is part of. That being said, she must get your consent if she ever records a conversation that both of you share.
This is only an Avvo answer. I am not getting paid to give this response and am basing this response only on the information provided to me in the above question.