If she's just complaining about you speeding(or lack of), fine, let her get all pissed off. I won't do any good. If, however, you're cutting people off, not signaling, ect... then she has legitimate reason to complain.
My last ex, she drove slowly and obeyed the speed limit and all that stuff... while I always drove 10 over (sometimes more), and did some ocasional agressive lane changing. I told her I wouldn't complain if she didn't and it worked out fine in that aspect.