Frankly, I think it is a bit absurb to assume that if one half of the couple is domineering, then the other half is automatically perceived as a weakling. A 'masculine' female simply possesses a stronger/more demanding personality which I don't see as transcending gender boundaries unless she starts doing things like stuffing her pants or the likes.

An inpolitically correct and common way of referring to such females, especially in a social setting, will be "bitch" rather than stuff like "dyke" or "butch" anyway, thus further reinforcing the concept of feminity in spite of what the character may seem like.

If the relationship features both physically male and physically female counterparts, it's more logical than not to call them a man-woman couple. I just don't see a need to go right into their psyche to determine if there is gender-role reversal or even gender-role adoption. Besides, tough women characters are so much more appealing than your typical airhead/whiny female character XD;;

PS: Sarah Connor and Allen Ripley so rule.