MajesticFae and diamondcontrol, I think his desire for a younger and athletic woman was so that she would physically be able to control him through her strength and endurance. Thus her body type is an extension of her personality.

Lucyboy, I wouldn't rule out the pleasantly plump dommes either. She may have a nice set of toned muscles underneath that you haven't noticed. For the most part it sounds like you have been running into dommes that prefer cuckolding more than anything.