It just occurred to me that they can't be marans as you said the eggs were lighter in color. My guess is they are cochins or Cochin mixes. They do come in birchen, and Cochin eggs can vary from light to medium brown.
He's probably afraid of her. Some roosters just breed what is easy. I'm not too fond of those roosters. Yours will make the one bare backed pretty quickly. Even if he mated both it would be too much on them. Roosters mate a lot throughout the day.