Any suggestions...need help with doggie style?

I am a 39 year old man. I have been married 2 times and divorced 2 times, so the amount of woman i have been with in the last 20 years has been limited. Anyway, I always here people talk about how much they like doggiestyle, and I have always had problems in this position. I am a well indowed and most of the woman I done dogiestyle with, I really hurt them? It causes all kind of pain for them, weather i go slow or fast, hard or soft. I can figure it out. Now I am also 6 feet tall, and like shorter women. Do you think this is the problem? Any suggestions. I dont lke being limited to only a few positions.....