I appreciate your email and think it is very brave of you to start facing these issues. One way to begin understanding the lying is that for years you kept the abuse a secret. This, along with growing up in a dysfunctional family created an internal truth that had to hidden to the outside world. Since the beginning of your “lying” started in childhood it makes since that the original dynamics of the abuse and dysfunction may have been what forged this coping mechanism. My experience in this matter is that learning how to cope as a child by lying becomes a style of interfacing in the world.
I would highly recommend some individual therapy to sort through the origins of this style — and to find ways to begin sorting through this compulsion. There is some interesting research that expressive writing may be one way you might enhance your therapeutic process.